Oldsmobile Aurora Normal Operating Temp?

[The Professa]

I had the water pump, water pump housing cover, tensior, spark plugs, and wires replaced on my Aurora last week after the water pump failed and the car ran hot. I now have the car back and it is operating at about 220 degrees. We had no cooling related problems out of this car until this month when the weather became extremely hot here in Mississippi. We have been at around 98 degrees with 95% plus humidity with a heat index of about 105 degress. I tried idling the car with the cap of the surge tank to remove any air and it is still running at about 220. Suspecting a thermostat problem, I tried idling the engine in drive in an effort to open the thermostat but the gauge stayed constant. The car has 205K but the engine seems to have a lot of life left in it. Any suggestions?
!998 Aurora 4.0 V8

 

[change2E85]

I'm having the same issue on my 1995. Runs around 220 degrees. My radiator was replaced last year. I think it may be the themostat. Mine still has the orignial from the factory. Only 70,000 miles, not much has been replaced.

 

[chemicall]

stock should be 195 I believe...Get a 180 and be done with it, won't overheat in the summer, and will still warm up fairly decent and quick in the winter.

 

[xjsman89]

Stock operating temp is 200 degrees. 220 isn't that big of a deal, mine does that sometimes in heavy stop-and-go traffic. I wouldn't be too worried about it, just watch it. If it creeps up any higher than 220 I would be careful. Pull over and turn her off if you creep into the red zone (280+). Overheating kills our cars.

 

[change2E85]

I did some more research and found out what some of the contibuting factors may be causing the Aurora to run at 220:

Bad Plugs
Bad Wires
Weak coils
Cat clogged

I replaced the plugs and wires tonight so I'll see how it performs tomorrow. Don't use irridium plugs. Stick with factory platinums. The irridium plugs made it run really bad so took them back and got OEM. Runs nice so far.

 

[change2E85]

Temp still goes to 220. I'm going to replace all of the the cooling hoses. I read that someone was having overheating issues and changing the hoses that connect to the overflow tank solved his issues. They are hard to find as GM and Gates have discontinued.

 

[G2Northstar]

I had the water pump, water pump housing cover, tensior, spark plugs, and wires replaced on my Aurora last week after the water pump failed and the car ran hot.
!998 Aurora 4.0 V8

I'm curious what the water pump sounded like when it was failing and under what engine speed was it most noticeable, etc.

Thanks!

 

[G2Northstar]

stock should be 195 I believe...Get a 180 and be done with it, won't overheat in the summer, and will still warm up fairly decent and quick in the winter.

It's worthy to mention that this could and would likely reduce MPG, especially in winter. A lower than stock or spec t-stat will confuse the computer and could cause it to stay in enrichment mode. This will also likely increase coolant temp due to the unburned fuel in the exhaust and ruin the catalytic converter all that much faster-- and the 02 sensors; there's 4 of them.

With that said every car is engineered differently, but the principles apply. It might be possible to reduce the temp rating by one setting, say going from a 205F to a 195F w/o any negative effects. If the cooling system isn't in good shape this will likely be a moot point.

So, do those coolant flushes every couple of years. Don't listen to the advertising: our coolant lasts " 5yrs or 150K miles". I've fixed enough vehicles to know better and luckily they've all been customers and not mine.

I've had good luck with Redline Water Wetter and highly recommend it for add'l cooling performance/effectiveness. There are several companies that make similar product.

Best of luck.

 

[G2Northstar]

stock should be 195 I believe...Get a 180 and be done with it, won't overheat in the summer, and will still warm up fairly decent and quick in the winter.

Second Response:

Looks like your're right on the money, at least in terms of what T-stat to use. My 1996 Owners Manual states it's a 180F, on page 6-69. I would have thought it would have been a 195F or higher.

It would make sense the operating temperature is about 200F, depending on ambient conditinos. However for an accurate temp reading a scanner can read live data. It's likely there is some difference between the two, perhaps enough to make someonce concerned.

With what I said before, the principle applies, so using a 160F T-stat could cause driveability problems and reduced MPG.


Thanks again.

 

[change2E85]

Saturday morning went to the Aurora and it had dumped the entire contents of the radiator on the road. I had never seen such green antifreeze before. I had a gallon of 50-50 and poured it in and followed it up with 3/4 a gallon of water. Drove the car about 10 miles to my mechanic. The engine ran under 200 which was a total shock to me. After discussing it with my mechanic, he said that too much antifreeze and not enough water can cause an engine to run hot. So try increasing the water content of the cooling system - it may help out.

My mechanic is going to replace all rubber in the cooling system and fix the leak and put in the correct mixture of antifreeze to water. Hopefully it will run within normal temps.

 

[G2Northstar]

Saturday morning went to the Aurora and it had dumped the entire contents of the radiator on the road. I had never seen such green antifreeze before. I had a gallon of 50-50 and poured it in and followed it up with 3/4 a gallon of water. Drove the car about 10 miles to my mechanic. The engine ran under 200 which was a total shock to me. After discussing it with my mechanic, he said that too much antifreeze and not enough water can cause an engine to run hot. So try increasing the water content of the cooling system - it may help out.

My mechanic is going to replace all rubber in the cooling system and fix the leak and put in the correct mixture of antifreeze to water. Hopefully it will run within normal temps.

Without knowing the history, or even the condition of why it boiled over, it's very unlikely the mix ratio will have such a significant effect. There are other issues at hand.

It's true: anything over 67% coolant will raise the temperature. The best cooling is with the least amount of "coolant". However a cooling system additive, such as Redline' Water Wetter (or the the like), will significantly lower coolant temp (via reducing surface tension, which aids heat transfer).

My Aurora boiled over (and shouldn't have), while on the car lift during semi-hot weather, after a short while of testing, also losing about 1+ gallons-- a joy to clean up. Added the Redline product and so far so good, but I still need to diag the cooling fans and verify the ECT temp with a scanner. If the fans are working, then it's probably time for a new T-stat, but not a "colder" one, just one that works properly.

If your car has a cooling problem, replacing the hoses won't fix anything. If the coolant was very low, fixing the leaks, of course will help. Hopefully neither of us has a cracked cylinder head. Your mechanic can use a gas sniffer or other test apparatus to confirm, by verifying excessive HC counts in the cooling system. Fingers crossed on that one!

Let us know what your tech finds out.

 

[change2E85]

Well I have replaced the radiator, 7 hoses, thermostat, both belts, coolant flush and increased the water content vs. coolant and it still runs hot. Even after converting it to ethanol, which burns considerable cooler than gasoline, it still reaches goes past 220 mark in traffic and on hot days it reaches 240. So I'm just going to give up at this point and enjoy driving it.

 

[xjsman89]

While it doesn't help too much, you can always remove your engine cover if you haven't already. Mine runs at 200 on the highway (the only true way to measure operating temp... too much stop-and-go in the city.) and it hits a solid 195 with the cover off. In the long run 5 degrees isn't a big change, but its something to consider.

 

[change2E85]

Yup. Took the cover off a long time ago.

 

[G-567701]

Nearly 90% of GM engines produced since 1947 have an operating temperature of at or around 200 to 220 degrees Fahrenheit the temperature is measured from the thermostat housing so not only is it including the coolant temperature it is also including the ambient temperature of the engine and whoever stated earlier that the mechanic said too much antifreeze will cause an engine to run hot is literally talking s*** out of their ass when you add water to antifreeze you are lowering the boiling point which in turn will cause your engine to run hotter 100% antifreeze at all times is the best method for cooling systems also when you are filling your cooling system up I would highly recommend you turn on your heater to full blast while the engine is running