Hyundai Repair: High temperatures..., head gasket problems, coolant level

Question
"Hey, I know this is not about a Hyundai, but I thought it might be similar
enough to ask.  I have a 91 Acura Integra.  Lately the temperature gauge has
been getting pretty high at times.  And then most of the time I'm driving around
its alright.  kind of like it just flares up once in a while.  Could this be one
or more of the temperature sensors going out?  Maybe a problem with the fan?
The radiator was replaced recently, so it's okay.  It seems that my heater has
become way less effective but I'm not sure if it has anything at all to do with
the cooling of the engine.  Based on these clues, what do you think I should
check out first?

Todd"


Answer
Hi, Todd.  I'll give you some general guidlines on how to check the cooling system, but you may want to try to find someone with some Acura-specific knowledge as well.  Normally, I'd direct you to the Acura or even Honda section of this site, but I see one has no experts and the other's expert won't return from vacation until May.  You might try hunting around for some Honda or Acura related message boards.  I know some Honda engines have head gasket problems, but have no specific experience and don't know which engines thay are.  I'd expect a problem with cooling the engine and heating the car to most likely have the same root cause.

As with any problem, you want to start with checking the basics.  After the engine cools, check your coolant level in the reservoir as well as the radiator.  If the coolant level in the radiator is low, this should be the primary suspect for your problems.  In that case, you should look to see where you're losing the coolant and make the appropriate repair.

If the coolant level is full or near full, start the car (with the cap still off) and observe the coolant in the radiator as the car warms up.  As the engine reaches operating temperature, the coolant should begin to flow in the radiator.  This is evidence that the thermostat is opening properly.  If your radiator cap is situated such that you cannot see the coolant flow, you can try feeling the radiator hoses.  One hose should be hot until the thermostat opens.  After the thermostat opens, both hoses should be hot.  If you don't get proper coolant flow, replace the thermostat.

Once the coolant starts flowing, you should begin looking for the radiator fans to operate.  This should occur prior to the coolant beginning to boil.  If the coolant begins to boil and forcibly push out (not just run-off due to expansion) of the radiator prior to the fans coming on, you'll need to investigate why the fans are not coming on.

I checked ALLDATA to see how the radiator fan is controlled, and it can be turned on by the coolant temperature switch, the a/c switch, or the cooling fan timer unit.  The coolant temperature switch screws into the engine by the distributor.  I also checked for TSBs related to overheating and found nothing of significance.