09-09-04, 04:34 PM
recently purchased 99 deville, put 500 miles on it and it started to over heat,
engine light came on before i cld pull off road. Cadillac shop told me that the head have lifted and need to be replaced or rebuilt (engine), has anyone tried block sealer to see if you can get heads to seal? Cadillac says it wont work because when you stress engine the heads will start to lift. I have had car running with a/c on and drove around neighborhood for 15 mins with it getting up to 225. Please help
09-09-04, 06:02 PM
Use the forum search feature in the tool bar and search using "overheating" "timeserts" "water pump" etc.... Lots there to read...
Lots of reasons for possible overheating besides a head gasket.....
Was the system full of coolant from the beginning...?? It may have been low unless you checked it when you started driving it.
If the cooling system is full did you check the coolant concentration?? If the coolant is not the correct 50/50 mix it could easily cause overheating symtoms. Check the coolant concentration with a refractometer...do not rely on a simple hydrometer check for coolant concentration if you are experiencing overheating problems.
Does the engine/cooling system loose coolant on an ongoing basis..i.e..is it always low even though you fill it up cold?? The coolant in the surge tank should be about 1.5 inches below the level of the pressure cap fitting cold. If the system is using coolant and requireing refilling constantly then it could just be leak somewhere. The system has a low coolant warning sensor in the surge tank...is that giving a warning of low coolant.
Beside the coolant level, you need to also check the water pump drive belt. It is at the rear of the engine. There is a separate drive belt just for the water pump. The belt may be cracked and/or the tensioner may not be adequately tensioning the water pump drive belt.
If the system does not loose coolant and is not low but overheats it could also be the thermostat sticking...easy to replace the stat.
225 isn't hot at all. The cooling fans do not even turn on until that point so 225 is perfectly normal for stop and go driving.
09-09-04, 06:59 PM
this car heated up to 260 when i shut it off last wk, had car towed to cad. dlr and had them do ck up, code show that it overheated, they tell me the heads lifted, car seems to run ok, my oil life went from 98 to 0 which i guess is another indicator that something went wrong. I am convinced from cadillac that its a head problem, just trying to find out if something will do temporay fix like a block seal product.
09-09-04, 10:46 PM
The oil life went to zero because of the severe overheat. The engine controller went into the limp home mode to protect the engine against damage from the severe overheat. That is perfectly normal in the case of an overheat. It doesn't prove anything other than the engine overheated.
If the engine is running fine now how could the "heads have lifted"...???
I would still suggest a little more diagnosis.
The "block sealers" sound too good to be true...because they are. Don't compound an overheating problem by dumping some crap like that into the cooling system. Find out what caused the overheat and fix that instead.
Is the engine using coolant...??? Are you having to add coolant constantly to it and/or does the low coolant warning come on?? If not, then the heads haven't "lifted"...
If the "heads lift" does that mean the same thing as a leaking head gasket??
09-10-04, 12:19 AM
I asked cadillac how they knew the heads lifted, they told me that they looked inside the intake and saw water. The "heads lifted" means the eng. has to be pulled, new time serts installed etc. I have only run this car approx 1/2 hr since i got it back with the bad news from the dealership. I drove it slowly around my neighborhood with a/c on, again cadillac says that as long as i baby it the heads shldnt lift much but they will under stress. I am a wholesaler and this is the 2nd time in 5 yrs I have bought a cad. with engine probs, the other car i put a new motor in, i dont want to do same with this one, thats why i am asking about sealants. I wld rather take it back to the auction and let someone else worry about it. I cant seem to get anyone to let me know if a sealant will work, cadillac says that is wont, that the moment someone gets on it or goes up a mtn. it will start leaking.
09-10-04, 12:49 AM
I would recommend that you put fresh coolant in the sytem and install the coolant system supplement/sealer that is installed at the factory and that is recommended in the service manual and see if that stops the coolant seepage described that is under the intake. No way is cooling getting into the intake manifold...they must mean the valley of the block under the intake manifold. If there is some coolant seepage there it simply could be a bit of porosity in the casting or something. The coolant supplement is designed to seal such voids that are relatively common in aluminum castings. The coolant supplement is purchased at a GM dealer ...ask for the coolant supplement pellets...they are probably several dollars for 6 of them or so. Or...go to Walmart and find the BarsLeaks "golden seal" powder in the clear tube found in the auto section. Buy two tubes of the BarsLeaks..same stuff as the GM pellets. Install the supplement/sealer into a radiator hose....NOT into the surge tank. Simply disconnect a rad hose, dump the supplement into the hose and reinstall the hose. Top off the coolant with 50/50 to replace any that was lost. Run the engine and see if the coolant loss disappears. It probably will.
The coolant may have been low due to a slow seepage. That is what caused the overheat. Fixing the seepage with the sealer will stop the leak and prevent the coolant from getting low.
If the heads are indeed "lifting" as you say then I would expect some coolant loss into the combustion chambers, white smoke out the tail pipe, over pressurization of the coolant system due to combustion gases entering it, etc... Blown head gaskets usually do not manifest themselves as coolant seepage into the valley of the engine. That sounds more like a porosity or cold shut in the casting that is harmless if sealed with the sealer.
There is lots on this in the archives. Use the search feature in the forum tool bar and search on "coolant supplement" and read my posts.