Q: When installing a new water pump and thermostat on my 1989 Pontiac grand Prix should I use gasket sealer or silicone grease

asked by on

I'm not sure if I should use gasket sealer or silicone grease when I've replaced my thermostat and water pump on my 1989 Pontiac grand Prix and don't know if that might be why it looks like coolant is still leaking from the brand new water pump I just installed
My car has a manual transmission.

In your application, the new thermostat comes with a new rubber seal which is the entire gasketing solution for the thermostat housing. Nothing should be added as that may interfere with the seal. The water pump uses a paper/fiber gasket. So long as the mating surfaces on the pump and engine are perfectly smooth, have no pitting, are clean and down to bright aluminum, and are not warped, there is no need to coat the paper gasket with RTV sealant. If there are defects in the metal surfaces, sealant will help but if no defects are present the sealant is superfluous; the gasket makes the seal. A leak proof seal with a paper gasket in this application requires that a torque wrench be used to tighten the pump bolts in sequence to 89 inch pounds (7.4 ft. lbs). YourMechanic can dispatch a certified mechanic to troubleshoot this if there is a leak. The service to request would be pump installation. Please let us know if you have further concerns or questions.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. When installing a new water pump and thermostat on my 1989 Pontiac grand Prix should I use gasket sealer or silicone grease

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Tailights and dash lights stopped working

Hi, check the fuse box and make sure that the fuse hasn't blown. If the fuse is okay, the switch may need to be replaced or there is a connection issue with the circuit. Over time corrosion can build up...

Q: Is it okay to drive while in need of a water pump?

Hello - if in fact, the water pump is leaking as has been diagnosed, it is definitely NOT a good idea to continue driving with a known water pump leak. Water pumps have become more reliable over the years for...

Q: Can hear fuel injection inside car

If you hear a humming noise, you could have a fuel pump issue. If you hear ticking, then it could be multiple things from a faulty fuel injector, to an engine issue. A diagnostic inspection of the noise from a...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...