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1998 Oldsmobile Aurora overheating?
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workman1974
New User
Jun 4, 2008, 12:57 PM
Post #1 of 8
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1998 Oldsmobile Aurora overheating?
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HI,
I have an 1998 Olds Aurora that is over heating and I can not find the problem. I have checked: The radiator fans work, the thermostat works, and the water looks like it is turn but did not open it up to check in detail. I did notice that the hose going to the water pump was cold, is that normal, and the other hose was hot, so the thermostat seems to open. I bought a cleaner to flush and clean the system but have not done it yet. I know it could be the head gasket but I see no leaks and it does not seem to lose any fluid? How can I check out for the head gasket? Thanks for all your help and input, Thanks Brian
(This post was edited by workman1974 on Jun 4, 2008, 12:58 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 4, 2008, 1:56 PM
Post #2 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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Lower hose cold is normal and upper warm/hot, normal. The other observations suggest thermostat and radiator are basically working - how well still unknown.
Ok: It's overheating so what are you noticing other than just the gauge? Don't allow it to overheat if at all possible. Is coolant level proper at recovery tank? This car may or may not have a cap on the radiator itself but it may not be full there. It should be totally full all the time there out of your sight of course. Heater might not blow heat is a clue that coolant level is low, full of air or air bubbles from overheating or from gasses getting into cooling system thru failed head gasket.
Some tests are: Pressure test cooling system, check that radiator is full even if removing a hose up high is the only way. From cold, feel pressure at upper hose (nothing when cold) and feel if it pressures up real quickly - before it even has time to warm up and that's a clue that gasses are getting into cooling system. It normally builds up pressure as it warms up but not right off the bat.
If the system never builds up pressure or loses it quickly from a normal temp when shut down then it might be leaking out of sight or burning it thru head gasket and small amounts at a time don't always show themselves.
Flushing wouldn't hurt but I don't think that's the whole problem just yet. Let me/us know what you find and again DON'T allow overheating as that's just insult to injury,
T
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workman1974
New User
Jun 4, 2008, 6:37 PM
Post #3 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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HI Tom,
Thank you for all your input. I do not want it to overheat or try getting it that hot so I have been trying to be care with it so I do not warp a head or crack it. This car does not have a radiator cap, only on the recovery tank. Yes the fluid is fine. I had off the cap on the take to see if I would get any gas bubbles at idle, I did not notice any there but that does not mean gas in not getting in the system. I did notice after about 10 minutes I seen vapor or smoke coming out of the tank, not much and the gauge in the car was only about 150 so I was not sure what it was doing that for at that moment. I took it for a drive to get it to heat more fast and I return and had more pressure and fluid coming out of the recovery tank, maybe that cap is bad too not sure. I want to do a pressure test but do not know if I can with this system only having a screw cap on the recovery tank, I will go tomorrow and see if I can get a pressure tester for that car. I will also check on the top hose and see if the pressure builds up fast, thank you, I never had heard of that one. So tomorrow I will do more testing to see what it really is doing. Also do you or anyone know if "Alldatadiy" is a good site for diagrams, making repairs info, and codes for cars, is it worth the money, thanks again for all your help. Thanks Brian
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 4, 2008, 7:16 PM
Post #4 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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The guys here have assorted info so ask away with a new thread for different concerns. The All Data stuff is available thru them for a price - programs for all cars are expensive and I don't have direct access to them.
Libraries frequently do!
Pressure tester can be rented (free I think) from AutoZone or similar chain type parts stores.
It makes it tough when cars put the pressure cap on the recovery tank and more cars are doing that instead of on the radiator. It's fine but complicates how to know the rad is actually full itself or for burping out air when you do anything with the cooling system.
I'm concerned that you've noticed vapors at the recovery tank which is part of the pressure controlled system in this car. It shouldn't even be warm coolant over there in 10 minutes yet??
You do understand the concept of the recovery tanks - right? You know - they take air and whatever from the engine and radiator thru a small hose to the bottom of that tank which is supposed to only return liquid back when system cools, contracts and sucks it back - the idea is air out, liquid back all the time which means the rad and engine are supposed to always be free of air or any vapor. Air and or vapors will expand quickly and blow coolant in the way out to and up over the recovery tanks when things get messed up.
As you know air doesn't exchange heat worth a diddle so the engine overheats.
If it is a head gasket problem so be it. Best to minimize further damage and surely best to diagnose it right as it's a lot of $$ and effort to be wrong with that one!
Keep observing and see what a pressure test can find for you,
T
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workman1974
New User
Jun 5, 2008, 2:49 PM
Post #5 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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HI Tom,
OK, I check the upper hose cold had no pressure and then I started the car and run it for a few minutes and I could still squeeze the upper hose, I noticed it got a little harder but not much at all. I did the pressure test with a tester and gauge, the car says 15 psi so I had it full with fluid and tested at 15 psi, after about 6 minutes it did drop but only to 14 psi and then held there, which I thought it would lose more pressure. Is there a good way to check the water pump better, The belt is tight, the outside of the pump pulley turns, but I have not open it up. I am not sure what else to do now, I know a person that is a mechanic the will replace the head gasket cheaper at his home then at the garage he works at, so I do not know what to do right now, any suggestions now? thanks Brian
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 5, 2008, 3:48 PM
Post #6 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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It's good news but inconclusive with the pressure test. Hoses will expand a bit and drop a pound so that doesn't mean a leak. Unfortunately you should only pressure it to the cap's rating and the pressures on combustion can be in the hundreds and need that much pressure to leak or only does it at a certain temp and some only leak one direction to cause as much hair loss as possible as you are finding out!
If you still have the pressure tester, put in on and start the engine. Watch it from cold go up - it will but not so fast as you noted by hand. NOW WATCH IT UP TO THE RATED PRESSURE AND DON'T LET IT EXCEED THAT. Realease pressure from the device carefully and let it go again if it continues to rise when alread warmed up then that does point to the head gasket. You must be careful as releasing pressure can cause coolant to flash boil and you don't want to get burned by that. Use judgment and if it continues to build up I'd call it a diagnosis for a bad head gasket.
For water pump: Without look at it's fins and seeing that they either don't spin for some reason or are corroded down to an inadequate amount it might behave at low speeds or only high speeds or something. That problem is rare and not the first place to suspect but you shouldn't just assume it works properly. If coolant can flow to radiator and return thru it cooler at lower hose it must be doing something. Also, heater would not work well if water pump wasn't pumping but that could be air in system also.
Then there's the sniffer or detection stuff for exhaust/combustion gasses in the coolant and reservior things that may help close in on the diag. Can you friend help you pin this down for you to speed up the process of blaming a head gasket or not? I hate to see you be without a car over this any longer than needed but also don't want to rush out on the headgasket diag without being pretty dang sure.
For now try again with the pressure tester but as I said don't let it exceed that 15lbs. It will normally it allowed and then some other weak link will have a problem - enough hair loss already - right?
Another thing is to look at the spark plugs. One or more might be very different than the others and then pressure tests thru plug hole or compression testing can help.
Lot's of this stuff is second nature for those of us who have worked on stuff for all these years and it's hard to pin quickly and I'm half brain dead sometimes and might be missing some suggestion! This is hands on forum work, not just point, click, copy and paste some universal textbook something.
See what else you can find or notice and let's see what we can nail down,
T
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workman1974
New User
Jun 6, 2008, 10:19 PM
Post #7 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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HI Tom,
I did the pressure test with the car running and the PSI kept raising, so really everything I have done leads to head gaskets. I researched a lot online and found the the threads in the block for the head bolts go bad for this car and can cause a leak as well, This takes a repair plug kit to fix that, so I am really thinking to have that done and repair the gasket while they are doing that. I really feel this is the problem from all the test and from all your help. Thank you for all your help and I will have this guy repair those things on it. I was told from his friend he would repair the head gaskets for $250 because he does this everyday at work so he can do it so good now and so much he must think about it in his sleep. I have never heard of any one to do it for that price, so I need to speak with him first but it sound and looks like it is very easy for my car. Not a lot of things to take of to get to it. So it is easy to unassemble and not take a lot of time. I will have to let you know what he tells me after I speak with him. thanks again for all your help, You have helped me a lot, thanks Brian
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 7, 2008, 3:33 AM
Post #8 of 8
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Re: 1998 Oldsmobile Aurora overheating?
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the diag is closing in isn't it? You've done well to get all the info you could on this. True - some cars have bolts known for breaking, one time use only (kind of self torqued with one stretch) and things that someone who does this a lot will know and allow it to be done right and be done with this.
There's one thing worse than needing this job is to rush to diagnose it and then find out it wasn't the problem at all!
Good luck with the fix,
T
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