random overheating, but not

[bb58926]

anyone ever hear of a random fluctuation of the temp gauge but the car having pleant of fluid and not actually overheating. It only happens sometimes and I can turn the car off sometimes and it'll stop.when it happens though it sounds almost like a siren going down the road, and the higher the RPMs, the higher the noise, however, as the RPMs decrease the noise lags behind also decreases but not simultaneously....? help
*owned*

 

[Jim Henderson]

What do you mean sounds like a siren? What sounds like a siren? Belt, engine, steam, what? We need more info.

Are you sure your engine is not overheating? Just because the water isn't overflowing or blowing steam doesn't mean you are not running hot. Does your car go into limp home mode? Does the info panel tell you that engine power is reduced?

Could be a fan belt slipping(siren?) which may mean you have some coolant flow but maybe not enough. This usually means one of several things... The belt is worn out or glazed and needs to be replaced. The water pump is on it's way out. Some accessory on the belt has a bearing that is failing.

The temp gauge can indeed fluctuate wildly if your gauge is bad or the sensor is bad or you have a loose wire. How fast does it fluctuate? and How far?

Tell us more. Something sounds fishy and it isn't a siren.

Jim Henderson

 

[bb58926]

more info

well lemme see, the temp gauge will rise all the way to the top if I don't stop and cut the car off, only allowed it to one time, however, on that one time I immediately popped the hood and checked the block and it was definitely not over heating, my fluid levels were all good too.. and as for the siren sound, it is really unique and hard to explain but try imagining something like a siren in the distance, it isn't as loud but the tone rises as you give it gas, if you idle it'll wind down. It definitely doesn't sound like a belt either, ( I could be wrong, been there before). also, does anyone know what steps need to be taken in order to replace the weather stripping on the windowsw, mine has faded horribly and I can't find anything to cover/clean this with. :feedback
also, there are no warning lights tellling anything when this happens or "limp" mode..drives fine still..hope this helps

 

[eL eS]

maybe a pin hole in a hose or overflow container. That is my best guess. IIRC the 00/01 models had a problem with a hose breaking at a bend.

 

[Jim Henderson]

Hmmm, what I would do is remove any drive belts and see if the siren sound goes away. This assumes the car will run without the belts, most will. Keep in mind I haven't had enough diagnosis time with the LS to be authoritave, I am working off experience tinkering on all my vehicles over the past 30+ years.

If the siren goes away when the belt is off, then at least you will have localized it to one of the accessories on that belt. If the siren is still there then it is a hose(air or water) or something internal to the engine or tranny.

Does the siren go away if you shift into neutral and gas the engine? If so then it is the engine and related systems. If the siren goes away then it is the tranny.

Does the siren wind down in sync with engine speed or does it have a significant delay? A delay could indicate air or water leaks. No delay ties it to the engine and anything that spins with it.

I don't know our cars well enough, but I am suspecting steering pump or other accessory, or a tranny problem brewing, both of these noises can be thought of like a siren I suppose. If you are lucky it is just a hose or belt slippage.

Good Luck,

Jim Henderson

 

[bb58926]

heating

well I am not sure but it seems to me that if it were something with the engine that it would do it more frequently. Like I said, it only happens sometimes, and yes it is in Sync with the engine except for when winding down it lags behind the RPMs for a sec or two but doesn't completely go away. I feel like it might be a sticking thermostat becaus ethe gauge will go all the way up but the engine doesn't actually get overheated. no leaks anywhere that are visible, and as I said, it only happened about 4 times altogether now. nothing crucial.. Could it be a fan of some sort as it stats to register hot :soapbox: :repost: .?

 

[Lincolnlov]

BB,
Had a diesel once that had a wildly fluctuating temp guage but the engine never seemed to be overheating. However if you took the radiator cap off and reved the engine it would produce an Old Faithful. Culprit was a warped head that let compression into the water system. New head and a thorough cleaning of the diesel exhaust in the radiator solved the problem. Unfortunatelu that was big $$. Lincolnlov

 

[whatsupadrian]

I know exactly what you are talking about. You have the same problem I and several other members had, replace your overflow resivior assembly and that will fix the problem. The noise you are hearing is the fan. It gets stronger as you gas it more. Correct you are not actually overheating. The problem is narrowed to the resivior assembly, it may be the pressure cap not holding its 14lbs of pressure. Or it may be the sensor in the resivior, but i had the same problem and it was fixed under extended warranty. Just replaced my whole resivior assembly. Good luck. Heres how my problem would be...

I would start my car, cold day. start driving, 1/2 mile down the road my remp goes up and i get the little light on the temp gauge goes on. Driving a little longer and you go into reduced engine power. Turn car off and on and it goes back to normal, sometimes. Anyways i let that go on for about 2 months and the incidents just got more frequent.

Siren was a bad analogy. Its more of a humming sound as the hydraulic fan increases in spead as the RPMs raise and wind down behind the RPMs

 

[bb58926]

overheating!

well if it is that and I decide to replace the resevoir assembly.. ANyone have any idea about how much In may be looking at out of pocket?.. I have no warranty... :Bang

 

[DLS8K]

well if it is that and I decide to replace the resevoir assembly.. ANyone have any idea about how much In may be looking at out of pocket?.. I have no warranty... :Bang

When your car says it is overheating, check to see if your fan is spinning faster than when you first start it. Mine had that problem and am still waiting to get it fixed (its at the dealer now). If I were you, it might do you good to just take it in and have a tech diagnose it. Granted, it is money out of your pocket, but if the mechanic knows what he is doing, you'll be better off.

It is also worth a shot to take a laser thermometer and check the temps of your hoses........if they are running hot (like 240 degrees), then your car is overheating. If they are cold and your car is overheating..........thermostat. If everything is normal.........temp sensor. They will do all this at the FLM store AND run the computer on your car to make sure everything checks out with the res. pressure cap (they make tools to test those).

 

[fishbone1]

bb58926,

My 2000 LS with 77000 miles is doing the exact same thing as yours. Please let me know what you find.

 

[TN_LS_02_V8]

Sounds like my 02 V8's problem

See my thread I just posted .... LS 02 V8 Overheating.
I have attached a Word document of my little history of the problem