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Big Lug
Anonymous Poster
nickiehen@hotmail.com
Jun 25, 2007, 9:11 AM
Post #1 of 4
(1288 views)
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Engine running hot
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97 Grand Am
Engine running hot when on short trips,not as bad on highway but using some antifreeze don't see any under the car, have replaced the overflow cap, any suggestions on what to check next
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 25, 2007, 4:15 PM
Post #2 of 4
(1280 views)
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Re: Engine running hot
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Make sure coolant is full at the radiator first. Then to proper level at recovery tank. You said hot -- do you mean overheating or just the higher range of gauge? The fan must be operational for low speed as needed.
Consumption of anti-freeze without finding a leak is not the best of news. If this system uses a regular amount you need to find it. Check all hoses, water pump, radiator. See if the system even holds pressure. If not do a pressure test not to exceed the radiator cap's rating and look around then.
Don't let it run hot if at all possible. This may be a head gasket problem and it will only be worse if it really overheats. Hope not but rule out the seeable leaks first then on to test the gasket -- hit back and I'll give you some ideas on how to test for that if you aren't finding anything else,
T
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Guest
Anonymous Poster
Jun 26, 2007, 10:02 AM
Post #3 of 4
(1278 views)
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Re: Engine running hot
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No, just the higher range of the gauge and how would you know that the system is under pressure?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 26, 2007, 12:08 PM
Post #4 of 4
(1275 views)
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Re: Engine running hot
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With it cold just take a look at the radiator cap. It should look clean which is no proof but it's probably ok if not all gucked up. Put it back on with coolant all full and start the engine. Feel the upper radiator hose. It should be cold and you can squeeze it noticing lack of pressure. As the engine warms up it will get too warm (hot) to hold but with a glove or whatever sqeeze and you should notice that it's tight with pressure. If it builds up pressure in the first minute or so of running that's too fast and what may be happening is the head gasket it allowing some gasses into the cooling system and you might notice some bubbles in the recovery tank ongoing. That wouldn't be a good sign as that just about confirms there's a problem with the head gasket.
If it never builds up pressure it could be leaking, cap no good, or burning coolant in engine but not fast enough to see it out the tailpipe. You then have to put a pressure test on the system - cold best - to the probably 14-15lb pressure the cap would allow. See how long it holds -- engine off BTW. If it loses pressure it's leaking somewhere and you may find a hidden coolant leak that only drips out when you are driving along and goes un noticed. Water pumps can be funky like that too.
If nothing found pull the plugs out and one would probably much different than the others which sort of confirms a head gasket problems.
When any gasous gas, air or from engine gets in the cooling system it can't cool properly and will make you temp gauge read late sometimes as to how hot the engine really is. If you keep finding it low you can further confirm that gasses like exhaust or gasses from compressing fuel and air are in the cooling system. That's about enough to blame the head gasket which may not be just the head gasket and you really don't know till it's all apart. Hope that isn't it as that's fairly expensive and if the head was damaged from head it could need work or have to be replaced. They should always be sent to a machine shop to verify that they are true or they can just plane off a bit and make it true again in many cases if it's not right.
There is potential for this to get costly as you can see. Hope it's a hose or something simple.
Oh, a heater core can leak too. You would almost certainly have a strange smell or funny fogging on the windows or even a wet spot on the floor if so. You would have complained about the smell if that was the issue I think.
You should do everything to verify that a head gasket type problem is really it as it's too much work to be wrong. Use mirrors with lights or whatever it takes to look for a real leak. They leave trace marks/discoloration at the source and may even be wet when and if you find one.
Anything that contains coolant could leak and could then cause the erratic temps. Also note that it is not normal to consume coolant. From new and known full cars may take a top off just from some hose expansion but not all that much and should be stable thereafter.
Hope that helps and you find something simpler. As said -- taking care of this now may be an easy fix and ignoring it may really make problems.
Good luck,
T
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