By Herb Helbig, Chief Engineer—Viper (Retired)

Q: ?I own a 2005 Viper with 30,000 miles. I’ll be replacing the brake pads soon and I’m interested in your preference for brake pads (what brand?). Also, what pad material do you recommend for normal highway driving conditions versus severe track driving?

A: As I’ve said often, when I worked at SRT® we didn’t endorse aftermarket parts mostly because we didn’t have the time to thoroughly test them. For street driving, you can’t beat the Mopar® replacement pads. These are the same as the production parts that had all the benefits of SRT development testing. I know that the ACR development guys like the Mintex pads for track testing, so they might be worth a try if you’re spending a day at your favorite race track. The guys say they run the Mintex on the front with production pads out back for optimum balance. Since more heat is generated with the race pads, consider upgrading your brake fluid to a higher temperature rating and bleed the system more often.

Q: Recently I replaced the thermostat housing gasket in my 1995 RT/10. Normally the engine runs around 190°F. However, now it’s running at 220°F with the fan running continuously. I must have air in the system. What is the air-bleed procedure for this engine? Thanks for your help.

A: Before we talk about bleeding, you might want to check and make sure the T-stat is opening when it should. You can do this by putting it in a pot of water and heating it up until the stat opens up. Use a meat thermometer to track the temperature. Of course you have to tear the motor open to get it out so it’s a bit of a pain. The best way to bleed the early cars is to fill the system through the heater hose. Open up the heater valve and disconnect the incoming hose so you can fill the system through the heater core. The guys in our shop used to use a 5-gallon bucket sitting a few feet above the core. Start with a cold car. Don’t warm the car before you remove the hose. Let the engine idle so that the stat opens and keep filling until the air is purged. The disconnected hose can go back into the bucket so you don’t lose any coolant. I’m told that there are commercially available coolant system vacuum kits that may help with this situation. I’ve never used one but they should ?be available in most auto parts stores.

Q: I own a 2008 Viper SRT10.® The vehicle may sit as long as 7 months without being operated. Do you recommend fogging the engine? What ?is the procedure to disable the engine from starting so that I may crank the engine over without it firing up? Do you have any winterization recommendations for long-term storage of my Viper?

A: Everybody has their favorite long term storage tips. Look for an article in an upcoming issue of VIPER Magazine. To your specific questions: fogging the motor is not required for storage up to a year. Make sure that if you do it you use oil specifically designated for fogging, anything else, and you are at risk because of possible contamination of the catalysts. If you want to crank the motor over without firing, pull the Auto Shut Down (ASD) relays (2). They are located in the Power Distribution Center (PDC) under the hood. The PDC is a black box and has the fuses in it. Some other tips would include a good wax job including the wheels, complete interior wipe down using leather wipes on the seats and some kind of tire treatment for the sidewalls. Store with a full tank of fuel including stabilizer and make sure the car was nice and hot when you put it away. Leave the windows part way down, unlatch the top and leave the trunk or hatch open slightly. Put the car in sleep mode (later models only) and use a battery tender (not a trickle charger). Oh yeah, a heated garage would help as well.

Q: My 2000 GTS will not engage gears. I was driving the car and took the transmission out of gear, then it would not go back in any gear. When the engine is not started the shifter can move in any gear position but when started will no longer engage. I can put the vehicle in gear to start it (with difficulty), but there is no clutch play and the car just leaps forward. I believe the problem is the clutch because before it warmed-up the clutch was a little soft/weak, but when warmed-up, felt strong. What do you think is causing the problem?

A: Definitely sounds like clutch trouble. A couple of easy things to check: first, look for wetness or drips at the bottom of the bellhousing. If you see this, the Concentric Slave Cylinder (CSC) is leaking and may need to be replaced. Before you tear it apart though, make sure the bleeder screw on the CSC is tight and not leaking. The not so obvious would be to make sure the clutch line is routed away from the exhaust system as far as possible and has an insulation sleeve on it. Of course, make sure the reservoir has fluid and don’t be surprised if the fluid looks dark—that’s normal. Finally, the system may need to be re-bled, but you need to ask yourself how it got that way in the first place because it’s not normal.

By Herb Helbig, Chief Engineer—Viper (Retired)

Q: ?I have a 2005 convertible Viper that just turned 19,000 miles. The A/C works great around the city; however, on long drives and high speeds the vehicle gradually loses all blowing capacity coming from the vents (decrease in air velocity). The cab temperature eventually reaches a point were the windows need to be lowered. This occurs typically after about 20 to 30 minutes of driving. I adjust the fan level to max, but I can only feel the coolness at the vent, and I can hear the blower working, but there is no air flow coming from the vents. If I stop the car and let it sit for 15 to 30 minutes, it will work again, but as soon as I get back on the highway, it does it all over again. If the problem is with the vehicle’s vacuum system, how can this be corrected? Or is it something else? I would greatly appreciate your help!

A: This sounds like it might be a problem with the duct work—especially since the A/C works well around town. Look for a restriction when you are experiencing the reduced-flow. Look at the intake area near the base of the windshield near the intake box. Good luck.

Q: I own a 2008 Viper SRT10® convertible with a set of Eibach springs installed. The vehicle has been lowered 1 inch. Typically, when I release the clutch quickly—at 2 to 3000 rpm rolling in first gear at around 20 mph—the vehicle wheel hops and I feel like I’m destroying the rear suspension. How can I correct this problem? The tire pressure in all four tires is at 30 psi.

A: Assuming nothing else has been changed on the car’s suspension, the hop issue may stem from the change in axle shaft angle because of lowering the car. Make sure that the fasteners are all retorqued properly—especially the shocks and control arms. If the Eibach spring rates are different than the stock springs, that may contribute significantly. Additionally, make sure the shocks are in good shape and show no signs of leakage.

Q: I’m the new owner of a 2006 Viper SRT10 coupe. The vehicle is black with silver stripe option M91. I need to know the Chrysler touch up paint part number for the M91 silver stripes as my dealer and local body shops are unable to find it. Also, what is the correct oil capacity for the 8.3L engine? My service manual shows 11 quarts; owner’s manual, 10 quarts; and 2006 brochure, 10.4 quarts—all with filter change.

A: The paint you are looking for is VA9. My paint expert suggested that you try to find a Dupont paint. This will give you the best match. The proper oil capacity for your car is 10.5 quarts with a filter change.

Q: After completing a hard run in my ’97 GTS, I noticed transmission fluid dripping from the transmission. The transmission fluid was changed recently. Is it possible the transmission was overfilled? If so, could this damage the transmission?

A: I’m assuming you had your car on a road course. You didn’t say what area the fluid was leaking from on the transmission. Most likely it’s coming from the vent which is on top of the trans. It’s possible it was overfilled, but it is also possible that the vent was dislodged during reinstallation. You need to take a look and see if the vent is still attached properly. Not easy to do, but you might be able to see it through the shifter opening.

Q: I have 4,000 miles on my 2009 SRT10. I recently smoked the clutch on a steep incline. During normal driving I still smell a burning odor; however, the vehicle still shifts fine. Do I need a new clutch?

A: Probably not. The dual disc clutch is pretty robust. The smell will probably take a while to dissipate but should eventually go away. As long as the car launches okay and shifts fine, you should be good to go.

Q: I own a 1996 GTS and I’m considering installing a Mopar® Cat-BackTM exhaust system (P5007274). How much horsepower could the engine gain with this system? Please mention any benefits and drawbacks for this system. Do you recommend any other Mopar parts to increase horsepower?

A: Assuming your car is totally stock, the system should be good for 5 hp at the flywheel. The reason that the number is so small is that the stock system is very low restriction. Benefits will include better sound quality and perhaps reduced sill heat. On the down side, you may experience some exhaust drone on the highway. If it’s bothersome, try shifting up a gear. Some other parts you might consider are rocker arms with a different ratio, camshaft and ported heads. With these changes, the addition of the exhaust system would yield a 25-30 hp increase.

By Herb Helbig, Chief Engineer—Viper (Retired)

Q: I own a 2006 SRT10® convertible with 18,000 miles. I have three (3) questions:

1. I’m considering a Corsa exhaust which requires removing the crossover. I’m reading mixed reviews on removing the crossover—some say it works fine and also significantly reduces cabin heat, while others claim removing the crossover sacrifices low-end power/torque. Is it advisable to remove the crossover?

2. When raising the windows the leading edge traps in the inner edge of the rubber triangular guide and folds the inner edge toward the window pane. It used to snap back into position, but the passenger side eventually deformed and stayed bent in. I had it replaced under warranty, but the new guide still does the same thing. How can this interference be prevented?

3. The rubber boot at the transmission has cracked. I ordered a new part but found that I cannot seem to replace it from the top side. Is it possible to replace from above or does the tranny need to be pulled and the boot replaced from below?

A: 1. We have not had the luxury of trying all the different exhaust systems available for Viper. The Corsa has never been tested by our team, so it isn’t fair to render a judgment. Just keep in mind that when you remove the crossover, the car will make more noise than is allowable under the federal guideline.

2. With regard to the window seal, the dealer needs to adjust either the flap or the glass to eliminate the folding. You might also try a little silicone lubricant on the guide to reduce the friction.

3. My experts at SRT® tell me that the environmental boot in the tunnel can be changed from the top. You have to remove the console top bezel and drill out the rivets and re-rivet the new piece in. If the crack is a small one, consider sealing it with some high-temp silicone sealer.

Q: It seems like it’s the convertible top or something similar, but I hear a clunking coming from the right rear of my 2006 SRT10® when I go over bumps. The previous owner took the car into the dealer and the report said they found it to be normal for the convertibles. Can you confirm this?

A: No clunk is normal. We didn’t build the top to make noise. A clunk coming from that right rear could be a lot of things. First try and isolate the noise inside versus outside and high in the car or low. Things to think about: loose shock, loose sway bar, check brake caliper etc. If you think it really is the top, look for wear marks where the top links might be rubbing, something may have come loose.

Q: What is the top speed that the 2008 Viper coupe can reach in a mile? I cannot find any information about the top speed on a Viper. In the Summer 2009 issue of VM there was a story about a Viper going 200 mph for the mile at the Silver State High Noon Shootout. I did the Texas Mile and managed 165 mph and I hope to go faster with some help on how to drive the Viper in the mile. Thanks for any help with this.

A: The top speed for the ’08 and ’09 is just over 200 mph, but it takes longer than a mile to reach top speed. The 600 hp coupe can probably reach 170 to 175 mph in the standing mile—like the Texas Mile. It might take another mile or so to wring out that last 25 mph.

Q: We have a 1997 GTS with about 22,000 miles on it. The speedo works sometimes—usually when you first start off it will either register, or not. Usually if you start off and it works it will stay that way. One time it went from not working to working—while driving on a somewhat rough road. I’ve been under the car and unplugged and replugged the two plugs closest to the speed sensor, and inspected for loose wires. Where else should I look? We’ve owned the car for about 17 months and the problem started about eight months ago.

A: Continue to look for a faulty connection, possibly at the back of the speedometer in the dash. It is also possible that the speed sensor has a problem and might need to be replaced.

Q: I have a 1992 Viper with 48,000 miles. I noticed Chrysler TSB 21-06-98 calls for Mopar Synthetic Manual Transmission Lubricant, part no. 04874459, for 1994–98 Viper manual transmissions experiencing a neutral rattle. Why does the TSB not include 1992 and 1993 model year Vipers? Can I service my 1992 Viper manual transmission with part no. 04874459 or should I continue to use ATF?

A: If you are not having the neutral rattle condition, stay with the ATF. The ‘92 and ‘93 cars were not experiencing any issues of this type which might explain why they were not included. It’s possible there may be some compatibility issues with some components in the earlier trannies.

Q: My 1996 Viper GTS has 32,000 miles. Recently the engine has been“cutting out” during hard acceleration. No problems during moderate acceleration, and the engine idles like new. I suspect it may be a coil problem; however, I’ve not noticed any coil leakage. Will a defective coil always show oil residue? Wires, connections and spark plugs all appear to be good (original). Any thoughts regarding what could cause the problem?

A: With the problem being related to hard acceleration, think about the motor torquing over and perhaps stretching a wire or connection and causing a break in continuity. Look for a torn mount either on the motor or the transmission.

Your technical questions are always welcome. Please remember to indicate the body style, model year and mileage for your Viper.

Tech Notes Editor
VIPER Magazine
PO Box 24425
Shawnee Mission, KS  66283
E-mail: [email protected]
Fax: (248) 499-1950

By Herb Helbig, Chief Engineer—Viper (Retired)

Q: Just picked up a 1998 GTS. I have surging in 5th and 6th gear at around 60 mph. I also have bucking at low speeds. I can’t find information that spells out the exact procedure to sync the throttle bodies for a GEN II. Can you help?

A: As far as I know, there is no procedure for syncing the throttle bodies on the single throttle cable engine. However, it’s pretty straight forward. The twin throttle bodies are connected by a cross shaft which has a bit of adjustment in it. The cable works the driver’s side TB and the throttle position sensor is on the passenger side TB. Make sure that as soon as the cable moves the driver’s side TB, the passenger side TB is also moving. If this is not the case, bucking is one side effect. Also make sure that when the throttle pedal is released both throttle blades are closed.

Q: It seems like it’s the convertible top or something similar, but I hear a clunking coming from the right rear of my 2006 SRT10® when I go over bumps. The previous owner took the car into the dealer and the report said they found it to be normal for the convertibles. Can you confirm this?

A: No clunk is normal. We didn’t build the top to make noise. A clunk coming from that right rear could be a lot of things. First try and isolate the noise inside versus outside and high in the car or low. Things to think about: loose shock, loose sway bar, check brake caliper etc. If you think it really is the top, look for wear marks where the top links might be rubbing, something may have come loose.

Q: I had the car in for service today and all went well until I noticed on the way home that the oil (temp) gauge was not working. I let the car get to temp and drove it a bit. There was plenty of oil and plenty of pressure. What’s really weird is that when I turn the key to on just before starting all the gauges including the oil gauge are reading correctly. Once I start it up though the oil temp gauge slowly falls back to under 120 and doesn’t move. Any idea what the problem is?

A: My guess would be a faulty sensor or possibly a connector problem at the temp sensor. I’ll admit that if you let the car warm up, shut it off and then just put the key in and get a good read from the gauge is confusing. That may be a more complicated electrical problem.

Q: I own a 1999 Viper GTS coupe with 20,000 miles on the odometer. I have a condition with the car’s HVAC system that has remained with the vehicle since it was new, but always thought it was a normal trait of the Viper. The condition occurs with the temperature knob in the cool position, while the A/C is on or off. The cool air coming thru the ducts suddenly becomes “very warm” for a period of approximately 20-30 seconds and then gradually starts to become cool again. This could happen about two times in the span of an hour on a long drive. Is this a normal condition? Can this problem be ratified with an upgraded Mopar part?

A: If the condition of warm air happens under heavy acceleration, the condition is normal. In order to deliver maximum power under heavy acceleration, the electronics temporarily shut down the compressor so the load is eliminated. If this is not the case, it sounds like the vacuum signal is changing at the HVAC unit. If that’s the case the dealer will need to check it out. If you’re sure it’s with the A/C on or off, then it’s time to visit the dealer.

Q: I own a 1995 Dodge Viper with 10,000 miles on it. I do a little autocross and road racing with it. Is there a good way of lowering it a little? I have a set of 2003 10-spoke wheels and stock tires and would like to have a little less ground clearance.

A: Due to the suspension design, there is no easy way to lower the car. You could swap a set of ACR shocks on and that would allow you to lower the adjustable spring seat. Otherwise you’d have to come up with a shorter set of springs and swap them on … not an easy job.

Q: I recently purchased a new 2009 Viper coupe and have decided to garage the car closer to my work rather than my home (two different cities). The problem is the garage entrance (commercial underground garage) is inclined and where the inclined ramp meets the garage floor is a rather sharp angle. Standard passenger cars do not scrape the front, however, the Viper with its front air intakes being so low, might pose a problem. I was thinking of air shocks for the front to add lift. Should you need it, I can determine the angle at the garage ramp and entrance. I was wondering if you have encountered this question in the past and have any recommendations.

A: There is no air shock that I know of that would fit your car, so there is no easy way to raise the front end. I’ve heard guys with this problem end up approaching the ramp at an angle that gets one of the wheels up first and allows a more gradual transition up the ramp … hope that helps.

Your technical questions are always welcome. Please remember to indicate the body style, model year and mileage for your Viper.

Tech Notes Editor
VIPER Magazine
PO Box 24425
Shawnee Mission, KS  66283
E-mail: [email protected]
Fax: (248) 499-1950

By Herb Helbig, Chief Engineer—Viper

Editor’s Note: In order to provide better answers for your questions, don’t forget to mention the year, body style and mileage of your Viper.

Q: After becoming more and more familiar with my 1998 Viper GTS I have noticed the passenger door has become difficult to shut. It seems that it needs to be adjusted, as, if I simply gently push it shut, it won’t close properly. If I hold it up as I push it shut all the way, then it shuts no problem. When I am parked on any kind of incline, the driver’s side doesn’t seem to stay open but the passenger side does. I can certainly live with these problems but I would like to get them addressed if there are simple things I can do to adjust them.

A: The passenger door sounds like it has sagged a bit. This can be easily fixed by adjusting the door hinge. Usually, this is a two-person job. You need to make sure that you only loosen the hinge bolts slightly so that the door doesn’t fall further out of adjustment. The job itself will be a bit of trial and error.

Q: After driving in the extreme heat here, I noticed that my car is running awfully hot. With the A/C on, it runs up to the notch before the red hot line. Where I live is in the mid-high 90s right now and the elevation is around 3,600 feet-plus. I took my car to a local shop to flush, refill and pressure test the coolant system. Today, it’s running hotter than ever. If 190°F is normal, is up to that notch way too hot?

A: I’m going to assume you’re Viper is an older model and built before 2003. If the car runs normally and it does not put the needle up as high when the ambient temperatures are lower, say 75°F, then you are probably OK. The car is just reacting to the high ambient temperature. Also, if the needle stays up near the mark prior to the red zone and doesn’t move higher but just stays there, that’s all right too. You must make sure that no air is trapped in the coolant system.

Q: I normally drive with my hands on the wheel and have never really noticed how much movement there is in the shifter when not shifting. I was lazy with my hand the other day and noticed that at about 2,000 rpm, if I floor it, the shifter pulls toward the passenger side about 3/4 to 1 inch whether in 2nd or 3rd gear. Is this amount of shifter movement normal?

A: The amount of movement you’re talking about sounds high. Of course, there’s always some movement, especially with high loads. I would look at the trans mount and make sure the rubber isn’t cracked. Also look at both engine mounts. If any of the three have started to separate, you’ll get excess shifter movement.

Q: I pulled the car out of the garage to let it warm up and circulate fluids. When I went to pull it back in, the clutch felt mushy. When I started to let it out, the car lurched forward and stalled. I pumped the pedal to regain resistance and got it back in the garage. When I went to pull the cap off the reservoir I noticed fluid had been leaking out around the cap. The fluid is also olive drab green in appearance. My question is that since I recently did a full cat delete and don’t know the clutch line locations, could it just be boiling?

A: You didn’t mention if you installed headers when you deleted the cats. If you did you’re probably boiling the clutch fluid. You also didn’t mention the year of your car—some Vipers had a protective insulating sleeve over the clutch line as it passes by the exhaust manifold. Make sure that the sleeve has not been removed. Regardless, make sure that there is as much room as possible between the manifold and the line. I wouldn’t worry too much about the color of the fluid. Most cars do have the fluid turn dark.

Q: I noticed today when I was driving with my top up that in third gear, if I take it past 2,000 rpm, and especially above 3,000, when I let off the gas I get a very audible whine. It sounded like an electrical whine at first, so I shut off the radio, but it was still there. Put the clutch in and it goes away. This is the only gear I have noticed it in. I’m assuming if it was the rear end, then it should whine in any gear, not just third. Perhaps this is a normal sound?

A: The whine noise you’re hearing is most likely gear noise. Since it’s when you let off the throttle, we call it coast down gear noise. It can come from the trans or the rear axle. Although it can be annoying all cars have some and it usually doesn’t mean things are going to break. Typically, rear axle noise occurs at the same vehicle speed not rpm. So if it’s the axle you should get it in any gear but at the same vehicle speed. You mentioned third gear. If you don’t get the whine in fourth at the same vehicle speed it’s probably the trans. The same idea applies, just because it whines a little doesn’t mean it’s ready to break.

Your technical questions are always welcome. Please remember to indicate the body style, model year and mileage for your Viper.

Tech Notes Editor
VIPER Magazine
PO Box 24425
Shawnee Mission, KS  66283
E-mail: [email protected]
Fax: (248) 499-1950