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2002 Oldsmobile Aurora - Cracked Head vs. Not Cracked Head?!

Well, here is a story that you only dream about…maybe even have nightmares about LOL. I bought a 2002 Oldmobile Aurora from a woman off of Craigs List. It was close to 80 miles away and when I arrived I found out the car had been sitting since 2005. Via email she told me it starts and runs great, BUT when I arrived I found different. She listed the car for $2,000 but then when I had a issue and could not meet her the day we both had planned. She then emailed me and dropped the price to $600. For that price I jumped on it. I arrived and found the tires dry rotted, the Serpentine Belt missing and radiator hoses missing. The battery was so dead it would not jump. So after hemming and hawing…I ended up with the car for $400 because it could not turn over and the belt and radiator hoses were missing. A $200 tow later and I get it back to my house. The tow driver can not believe the price, so he hooks a pack to it to get a charge to the system…it reads 46,000 miles!

The owners had a divorce and the vehicle was part of their battles. The wife had got it in January 2009, but had no clue what to do with it. The water pump was replaced but the hoses to the radiator were missing and so was the pulley to the water pump and belt. So to make a long story short, I replaced them all with my father-in-law. He a retired guy that likes to tinker around.

Everything was put together and my wife drives it down the road and about 2 miles down the Display states “Engine Hot…Shutting Down A/C” then about 30 seconds later, it states chimes then states “Engine Hot…Idiling Engine”. We pulled it off the side of the road and cool it down. Get it back to the house. Cracked head we think…With the speed my father-in-law thinks it is by the spark plugs.

We take all the spark plugs out the next day, no moisture. No smoke comes from the tail pipes and no loss of fluid nor mixing is going on.

I go to get a kit to test the pressure. The guy at Autozone says no it it not a cracked head, but something to do with the coolant system. So I do not buy the kit. We instead flush the system. The car now drives about 5 miles before over heating. So we get it back yet again, cool the engine down and the next day…we decide it is nice in Upstate New york (80 degrees) and so my father-n-law suggests we run it in the driveway to see if it will over heat…1 hour fine…2 hours running fine…3 hours running fine!! So that is what stumps us, if it is a cracked head, shouldn’t it overheat idiling?

So here is the dilemma it idles and does not over heat, but as soon as it gets the tranny involved/drives it starts to overheat. Any suggestions?

What I’m wondering is why the water pump was replaced on a car with 46K miles on it? You’ll never know the correct reason, but it probably has something to do with your current problem.

Are you sure the thermostat is good? Three hours of idling with no overheat makes me think it’s OK, but you never know.

I wouldn’t think cracked head so much as leaking head gasket. Time to start pressure testing the cooling system and checking for compression leak-down.

The odds of a cracked head are near zero.
When overheating on the highway is the A/C in operation when this occurs? Are the cooling fans running if so?

Second question, and I’m not sure about this issue on this particular model of car.
Many late model vehicles over the last 20ish or so years are equipped with a small plastic air dam underneath the lower radiator support. If this air dam is missing (curbs, potholes, critter strikes, removed and discarded because of a “how important could it be” type of attitude) then overheating can occur at highway speeds.

A car can sit and idle all day long without overheating but once at an elevated speed overheating will set in because not enough air can be rammed upwards through the radiator with the missing air dam.
I don’t know if the Aurora is equipped with one of these or not, but a quick look underneath might not hurt?

An air dam can make a 30-40 degree difference in engine temps.

Here’s an example of an often overlooked air dam problem. For a Camaro and bit larger probably than what exists, or may have existed, on your Aurora.

I like this theory (really, I do), but how much “elevated speed” driving do you think happenes within 2 and 5 miles of home? Is that enough for a missing air dam to matter? I’m not an expert at this, but it seems like it should take more than 5 miles for a missing air dam to make a difference.

If I’m wrong, please correct me, ok4450. I learn lots of interesting things reading your posts, and maybe this is something I need to learn.

Sounds like the electric radiator cooling fan isn’t working.

Is that still the Northstar engine or did they change it. On my Northstar, the pulley for the pump is integral to the pump-so if it was missing? At any rate I would be very suspicious of the pump-not properly installed, leaking, etc. Especially if it was a hack job and half the parts missing.

With all of the issues though, I think you have to start at the beginning and cover all the bases. Flush the system to make sure the radiator is good and the engine passages are not blocked. Make sure the overflow tank is sealed, and everything else is ok. A pressure test would also be in order and that co2 test to check for a head gasket issue. I really think though its a pump issue. The fans shouldn’t come on that quick but if you have a pump problem or the pump belt it would heat up that fast, or if you had a blockage.

Two miles should not cause the car to overheat so what I’m wondering (even on the 5 mile scenario) would be if the car is really overheating at all or whether it’s case of a dashboard message center display gone stupid.

I have seen a few cars overheat within 5 miles on the missing air dam scenario. One of them was my youngest son’s Camaro. While calling from college he stated the car was fine in town/at idle but once at a steady speed the temperature would hit 230 and stay there.
He nursed the car home one weekend and an inspection showed the air dam was gone.

By some sheer fluke, the local Chevy dealer happened to have one in stock (must be a market for them?) and was open on Sat. Replaced the air dam and the temp dropped right back to a rock solid 195 and never varied even at 70 MPH on a 100 degree day.

Another weird one I’ve seen a couple of times is a cooling fan that runs backwards. At idle air will blow forward and cool the radiator. At speed, the fan’s backward’s air is being met head-on by airflow entering the front of the radiator. It becomes a stalemate. The first car I ran into this on was a SAAB.
The fan connector was a 2-prong that only fit one way. Someone during the manufacturing process had inserted the 2 wires into the plug in the wrong positions. This caused the DC motor to run backwards from it’s normal rotation.
No problem at idle/slow speed but on the open road they would seriously overheat.
(It’s unlikely the problem is this weird; just pointing out a potential goofy possibility.)