Tech Notes

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.

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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.

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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.

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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.