1.3 Engine Overheating

[Billjohn]

Originally Posted by alternator

So in case the thermostat is corroded, how easy is replacing it? And would that mean that my thermometer is giving me a false reading?

The reading is probably correct. If the thermostat is corroded (clogged) and doesn't function correctly then your engine is not getting the coolant it needs to stay at a normal temperature. It is an easy replacement. Just get a new one, some RTV (sealant) and a new gasket.

[alternator]

Ok ok, so how does the thermostat help cool the engine? Does it increase the coolant cycle inside the engine, or what?

[Billjohn]

Originally Posted by alternator

Ok ok, so how does the thermostat help cool the engine? Does it increase the coolant cycle inside the engine, or what?

Exactly. It controls the flow of the coolant.
Flowing too slow - the coolant doesn't get to the rad quick enough and in boils in the block.
Too fast and it doesn't get a chance to cool in the rad before it is pushed back nto the block.

The thermostat is supposed to try and keep the fluid travelling at a speed that will even out the temp and keep it at the desired level.

[squid]

does this vehicle have an electric fan in front of radiator?

[alternator]

Originally Posted by squid

does this vehicle have an electric fan in front of radiator?

Yes it does; a small one, it's attached to the A/C radiator.

[squid]

Check fan operation. I don't have a wiring diagram in front of me right now but generally the fan needs to be on when the a/c is on.
squid

[87samurai_dunn]

i had a similar problem and it turned out to be the clutch fan was dead and not engaging when hot, if i was you i would replace the thermostat because its only about 5 bucks and about a ten minute job and if that doesnt solve it get a new clutch fan and make sure thats working, as far as the a/c problem its just because its working the engine harder, and while idleing its not spinning so its getting it hot but while driving its air cooling, my 87 samurai did the same thing and i was starting to get worried but i just got the new clutch fan and its fine

[alternator]

Originally Posted by squid

Check fan operation. I don't have a wiring diagram in front of me right now but generally the fan needs to be on when the a/c is on.
squid

Yes, I checked that. It's working fine.

Originally Posted by 87samurai_dunn

i had a similar problem and it turned out to be the clutch fan was dead and not engaging when hot, if i was you i would replace the thermostat because its only about 5 bucks and about a ten minute job and if that doesnt solve it get a new clutch fan and make sure thats working, as far as the a/c problem its just because its working the engine harder, and while idleing its not spinning so its getting it hot but while driving its air cooling, my 87 samurai did the same thing and i was starting to get worried but i just got the new clutch fan and its fine

I'll do that. Replace the thermostat. Gotcha.

[Merlin93]

Both the thermostat and the fan clutch are common wear-out items. Replacing the thermostat every few years is good preventive medicine. [I once got too cheap and postponed doing it and lost an engine and car -- learn from my mistake. ]
A failed fan clutch can be harder to diagnose. One symptom is that the car gets hot at idle, but cools adequately while driving. You'll have to drain the coolant and remove the radiator to access the fan clutch bolts, but it's a pretty easy repair. New fan clutches are commonly available.

[alternator]

Originally Posted by Merlin93

Both the thermostat and the fan clutch are common wear-out items. Replacing the thermostat every few years is good preventive medicine. [I once got too cheap and postponed doing it and lost an engine and car -- learn from my mistake. ]
A failed fan clutch can be harder to diagnose. One symptom is that the car gets hot at idle, but cools adequately while driving. You'll have to drain the coolant and remove the radiator to access the fan clutch bolts, but it's a pretty easy repair. New fan clutches are commonly available.

How do you diagnose a problem in the fan clutch? I would imagine if the fan cannot be rotated while the engine is off means the fan clutch is in good shape, no?