FAQ: Engine Coolant Temperature & Fan Turn-On

But if your car does not usually run this hot, as you state, it's possible you may have some air pockets in the system that need to be purged. Did you use the air bleed screw on the thermostat housing to bleed off air in the system, once it warmed up to op temps and t-stat opened? Simply changing the coolant should not result in your running hotter than you used to.

Driving around town, the 180 will not be real effective unless you also have the fan turn-on settings modified to turn on at a lower temp. Factory settings are over 200deg turn-on. At hwy cruising speeds, the 180 will help, but not so much in slower city traffic.

Sounds like air in the coolant.


FYI Josh the Riv's water pump sits such that if there is any appreciable air in the cooling system it will develop a bubble at the pump, and then the pump will try to whirl the air rather than move coolant. So "burping" they system using the bleed screw is NOT optional. I assume, however, you did open the bleed screw, right?

Sometimes even though you 'burp' the system air is trapped elsewhere for whatever reason. Not a big deal -- let's jsut say the FIRST thing to try is just to burp it again.

Also look for coolant leaking out at the weep hole. If coolant weeps out, air usually seeps in. If you do have coolant weeping out you have to decide if it's time to replace the water pump. Lucky us, GM uses the same model WP on a bunch of cars - so they are not all that much.

Albertj

what temp is the radiator fan suppose to turn on at?

another thing. the vacuum canister for the excess fuel. if the lines got pinched would that cause my car to get alil warmer then normal?

long story short while making my FWI. i had to relocate the lines that run to the canister. i used sh*ty (not fuel rated) hose. just realized that, with engine bay hot + vacuum. they have gotten pinched. i will be changing them out later today for actual fuel hose.(should of known better) but while sitting in line at my kids school. engine temp shot up to almost 240. but i was sitting there for about 30 mins just idling before it happened. so i dont know when my fan actually came on, cause i have been having problems with it. so i will be changing it out shortly. so ya back to question 2.

I think the fan turns on low around 215, the OEM thermostat is either 195 or 205. Fans should be on high by 230. Or, the fans should be on when your A/C is on.

Did the temp gauge make it into the red?

These engines should be able to handle 240 without a problem, or so I've been told be various GM professionals...

ya the ac was on. i was sitting there for awhile. about 30 mins had passed and it was fine. about 10 mins after that the temp went up. i didnt have my scanner on me so i can really only guess what temp it was. i would say around 230-240. i have the 180t in. i have never seen past 210 b4. it scared the hell outa me. is there a way to make the fan come on sooner?

would the vacuum canister have any effects on temp or anything.

also the stock plastic hoses that run to the canister. would i be able to bend those. maybe heat them up in the oven or anything. im thinking maybe 350 for a few mins.

95ParkAveUltra wrote:

ya the ac was on. i was sitting there for awhile. about 30 mins had passed and it was fine. about 10 mins after that the temp went up. i didnt have my scanner on me so i can really only guess what temp it was. i would say around 230-240. i have the 180t in. i have never seen past 210 b4. it scared the hell outa me. is there a way to make the fan come on sooner.

Do you know, or did you look to see if cooling fans came on?
I would check for proper operation of the fans.
Also, it can't hurt to change out the thermostat, in case that is sticking.

Don't know if you can reprogram PCM on 95 PAU to change cooling fan settings.
I know on my 98 I had the settings changed after installing 180* tstat.
Maybe someone else knows.

My fans do not come on when AC is on. I agree with changing the t-stat. Could be an easy fix.

IIRC the FSM for 98 Riv states that cooling fan will come on when A/C is selected on if outside temp is above 48* F.
Don't have the book in front of me to double check!

check also to see if something else is wrong. like a bunch of crushed fins on the radiator, air in the coolant system, or a head gasket leak.

Albertj

Rickw wrote:

IIRC the FSM for 98 Riv states that cooling fan will come on when A/C is selected on if outside temp is above 48* F.
Don't have the book in front of me to double check!

Maybe so, but I never knew my fans worked until I programed them to come on at lower temps.

AA wrote:

............. I never knew my fans worked until I programed them to come on at lower temps.

Same here, my fans never once turned on the first year I had the Riv, even in 95deg summer heat. Eng temps never went above about 200-205.

Fans are supposed to come on with the A/C on when moving slower than a certain speed, and over a certain outside temp. It does have something to do with the pressure in the A/C system too, but I forget the specs exactly.

That's why when I first put a 180 Tstat in I never bothered to reprogram the PCM - if my A/C was on my fans were too, and so my engine temp was locked at 180 even sitting in traffic.

At any rate, 230-240 is not a temperature to be concerned about. These engines are designed to handle 260 before you have to worry.

You still have an issue with your fans though - could be the fan temp sending unit (not the same as the gauge/PCM temp sending unit IIRC the '95), and the fans should run when your A/C is on.

i turned the ac off when i noticed the temp. a quick drive home and i looked the fans where on but i was still at 215ish. i dont know if they were on with the ac or not. i will check l8r. i just put the 180 stat in not to long ago. normal temps i see in daily driving are 190-205 in these 90* days. i drove it last night when the outside temp was down to 85 and i never seen over the normal 180-190. i dont think the tstat is bad.

im thinking that the fans were on for most of the time i was sitting there. they might have clicked off causing the temp to rise like that. then clicking back on. i have noticed issues with it l8ly. (MAJOR voltage drain when it turns on) as soon as i get some extra cash i will go replace the fan motor to be on the safe side. if it happens again i will be alittle more concerned. thanks for the info. imma keep my scanner on me. to check the exact temp next time.

Quote :

At any rate, 230-240 is not a temperature to be concerned about. These engines are designed to handle 260 before you have to worry.

Maybe the temperature itself won't damage the block/heads, but I'd be concerned with these temps, because: A) something's not normal, causing this problem, and B) he's running a smaller SC pulley, so the heat will increase knock potential. Not saying the engine is damaged, but I would be concerned if it were my car.

I didn't see any mention above of the coolant level... Have you opened the radiator??

As far as the disparate accounts of fan function, in the Rivieras the fans (2) are wired with a series/parallel circuit. When the coolant reaches 215, parallel voltage is applied and both fans run at high speed (very noticeably.) Below 215, whenever the compressor is on in warm weather, the fans are run in series. In this way they each provide the other's "speed resistor" and they run on low speed. They are so quiet on low speed that they normally cannot be heard over the sound of the engine and the compressor clutch. More than likely, anyone who thinks their fans don't run with the A/C on has never actually looked under the hood at the time... or has a bad fuse/relay.

My cooling system works fine when driving, but when idleing the fans do not come on under the hood, and my temperature rises, Im fairly sure if I let it idle too long it will overheat. Any ideas?

what temps do you see after sitting? how about on the highway? what t-stst do you have in there?are the fans on when the A/C is on?

fan turn on for a stock car is like 210*, and it's normal for these engines to get hot sitting in traffic.
the only way to change when the fans turn on to keep the temps down is with a tuner.
i have found a mix of 30% coolant/70% H2O and a bottle of water wetter (redline) keeps me at ~178* on the highway with my 180 t-stat.(as long as it's under 90 outside) that temp was read with a scanner, not the car gauge too.
if you see lots of freezing weather in NC then 70% H20 will not work for you.

Mr.Riviera wrote:

what temps do you see after sitting? how about on the highway? what t-stst do you have in there?are the fans on when the A/C is on?

fan turn on for a stock car is like 210*, and it's normal for these engines to get hot sitting in traffic.
the only way to change when the fans turn on to keep the temps down is with a tuner.
i have found a mix of 30% coolant/70% H2O and a bottle of water wetter (redline) keeps me at ~178* on the highway with my 180 t-stat.(as long as it's under 90 outside) that temp was read with a scanner, not the car gauge too.
if you see lots of freezing weather in NC then 70% H20 will not work for you.

Gatorade quenches your thirst better...and it tastes better too.

albertj wrote: check also to see if something else is wrong. like a bunch of crushed fins on the radiator, air in the coolant system, or a head gasket leak.
just curious, why would a blow head gasket cause overheating???

and...is it me or do these 3.8 engines run hot? after a drive with the temp gauge stuck in the middle sometimes a little beyond,it sure gets hot! is that normal??

I do agree with A/C, 215*, and 230*, for that's what my car appears to do.
However, this Park Ave is pre-OBD II and a different platform, so it is very likely different from all of our '96+ Rivieras. In fact, I don't know what year they changed, but the earlier '92+ LeSabre/Park Ave engines used two different sized fans on individual circuits...

For what it's worth, here is the General's explanation for a '98 Riviera [& '98 Park Ave]

The PCM will complete the ground path for cooling fan relay #1 (low speed) under any of the following conditions:

* When engine coolant temperature exceeds 223°F [212*]
* When A/C is requested and ambient temperature is greater than 122°F [39*! But it's probably moot - My fans run on low any time I want A/C, so I'll bet the PCM is using the IAT sensor, not the ECC exterior temp sensor...]
* When A/C refrigerant pressure is greater than 190 psi
* When the ignition is off and engine coolant temperature is greater than 284°F

For high speed cooling fans operation, the PCM will delay control of the Cool Fan 2 Relay and Cool Fan #3 relay for 3 seconds. The 3 second delay ensures that the cooling fan electrical load will not exceed the capacity of the system. The PCM will complete the ground paths for cooling fan relays Cool Fan #1, Cool Fan #2 Relay and Cool Fan #3 under any of the following conditions:

* When engine coolant temperature exceeds 230°F [226*]
* When A/C refrigerant pressure is greater than 240 psi [224]

I recently sold my 95PA.(loved that car) it had the NA SeriesII engine.

On my PA the fans came on as soon as you turned the AC on

If I were you I would see if I could get the vehicle to heat up again.
Let it sit and idle and monitor the temps.

Also it has already mentioned (I think) but you could bleed the system and make sure there is not a air pocket in your coolant system.

You also can have your oil analyzed and find out if there is any coolant present in the oil.


Bert

robotennis61 wrote:

albertj wrote: check also to see if something else is wrong. like a bunch of crushed fins on the radiator, air in the coolant system, or a head gasket leak.
just curious, why would a blow head gasket cause overheating???

If the head gasket is blown, you are either losing coolant pressure, which is necessary, or forcing engine gases into the coolant, which will add heat and create bubbles which is also bad. Both of these symptoms will cause low coolant levels and that will cause more problems.


No, I don't think these engines run any hotter than any other modern engine. Remember, the factory is thinking about combustion chamber efficiency, and that means heat. They were designed to operate with coolant temps around 200.

If yours is running really hot, you might need to check some other parts of your cooling system, i.e. water pump vanes, radiator passages, fan operation...

Quote :

and...is it me or do these 3.8 engines run hot? after a drive with the temp gauge stuck in the middle sometimes a little beyond,it sure gets hot! is that normal??

200ºF is the middle mark. I think 210 is about normal in summer, although I would not go WOT at this temp, even stock.

new riv owner and first time poster here.....

i am slightly reassured to see others running warm and it's also nice to see that my fan turn on is normal ( 210ish).

i just got the car yesterday and already changed the stat to a 180*. it runs nice and cool but idling raises the temps to a bothersome level. i should say the temps here in MN right now is about 55* and it's still creeping up to 210-215* with extended idling time.

crossing my fingers i don't have any major problems.

nate