CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Overheating

My 1989 s10 pickup with the 4.3l has a overheating problem. when you drive it down the highway going 65+mph the gage says it is overheating very bad. it dont do anything out of the ordanary just the gage. but if you pull over for 5 second shut the truck off and restart it the gauge reads that it cooled down back to normaly. whats going on? please help me

Driving around with an overheating car can end up costing you big time. Do you really want to buy a new engine?

I am going to guess you have some air in the system, but no matter what, you want to have a competent mechanic check it out. BTW the fast lube places don’t hire competent mechanics.

I’ve had this same problem in the past. My freeze plugs were defective due to rust? on the engine block and I had them repaired/replaced. After having them replaced I had to flush the coolant many many times to get all the excess rust/debris from the cooling system and I experienced this same temp over heating. You first may just want to go ahead and replace the thermostat and then fill you radiator with water/antifreeze with the engine cold. I would let the engine then run to operating temp with the radiator cap off. When the thermostat opens to supply more water due to the increase in temperature you should notice the water level drop in the radiator. You can add more water/antifreeze at this point and reinstall the radiator cap. Also it helps to turn on your heater and set the heat temp setting all the way up which will allow more water flow through the heater core. You may have an air pocket here also. Give it a try because it worked for me

I think its’ a gauge problem. Buy or borrow an instant read infrared temperature gun and point it at the radiator in several places when the gauge shows too hot and again when it shows normal. If it reads the same you are not overheating.

I have heard some gauges have a built in dampening effect, theory being not to unnecessarily alarm drivers? Any validity to that? Could that explain the symptoms? Check fluid levels and get checked soon.