Cadillac Owners Forum banner

1 - 17 of 17 Posts

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #1
hi my cooling fans come on only when ac is on,could anyone tell me where do i find relay in charge of em fans when ac is off?its an eldorado 1998.thanks.:banghead:
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
69,483 Posts
Unless the engine overheats the ONLY time the fans will run constantly is when some A/C function is selected.

In your car the thermostat is set to begin at 188 and be fully open at 206. The fans are programmed to go to slow in traffic if the coolant temp reaches 224 and to fast at 236.

The fan circuits are hot at all times, so if you have just shut down after a drive in heavy traffic it's entirely possible that the fans will run for 10 - 15 seconds even with the key off - the engine passes off the excess heat to the coolant which is still circulating by normal convection, so the fans cool things down. With a 16 or 18 lb. pressure cap a 50/50 mix coolant boils at 265 degrees.
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #3
hi thanks a lot man.so looks like u know a lot about cars!im having this overheating problem when i go up hill for more then 15 minutes ,ive just put new thermostat in it and didnt try to go uphill yet,but i was driving today around the city and it started climbing up to 1 o'clock and then went back to 12,i did pressure test-no leaks,what could it be buddy?i real appreciate any help ppl!my water pump is new too btw.i took it to the dealership and just a shop dealership told me its all good,shop told me i need a new engine but they never even changed the thermostat so that make me doubt their knowledge about cars....dont really wanna buy a new car...i like this caddy .please HELP me people.THANKS!!!!!!!!!!!!!!!!!
 

·
Registered
1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
Joined
·
6,738 Posts
Check the small hose at the bottom of the coolant holding tank. It can plug up with crud and stop coolant circulation. Hose runs from that tank to a nipple on the engine. Remove it, engine cold, and verify the hose is clear and both nipples are not restricted. Its a by pass hose to lessen air getting trapped in the engine. Also that system requires that GM cooling system pellets be added thru the lower radiator hose when the coolant is changed every 2 years. If the sealant was added by mistake to the holding tank, it plugs up this small by pass hose.
 

·
Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
Joined
·
69,483 Posts
If you're city driving and the temp goes to just shy of 1 o'clock and comes back down, that's normal. Now, set some A/C function with the temp set at ??? 65 degrees. In P, pop the hood.....one or both fans should be purring in slow. Go for a drive. The temp should stay right on 12:00 or just a tick above.

Carnut wants you to make sure the small 3/8" cooling system purge line, from the surge tank to the water pump cover area, is clear. That line pisses coolant and any bubbles to the surge tank, keeping the main cooling jacket "solid" coolant. Keep the surge tank half full, COLD. If you overfill it, the expanding coolant has to go somewhere, so it blows out the surge tank cap relief and looks like boilover. Common mistake.

Saw your other post about missing.......Check your coil wires and spark plugs...ACDelco Platinum #41-950 ONLY. Click on the wire/coil diagrams. CRITICAL.
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #6
ty so much guys i will check all this tomorrow (playing poker)))):thumbsup:
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #7
what to look for when i check wires and spark plugs?what did u mean by critical????thanks.
 

·
Registered
1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
Joined
·
6,738 Posts
Critical meaning if the coils are miswired, it will miss. Critical meaning that spark plug and none other is to be used. Miss and runs warm as speed increases??? if this were a Honda I'd say leaking head gasket. Might be worthwhile to pray before the poker game! and its ok to be a gambler.
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #10
so i lost my poker games and went to the car.checked coils they look fine on the inside, the only thing i could find was that two of em were not all the way in on the sparks end(could that be the problem?)ill pray today and gonna take it tomorrow to the vail pass see if its gonna be overheating.that line from the tank that goes to the engine was clear too!and fans run with ac on (both)and when it climbed to 1 o'clock i pulled over and popped the hood they were spinning ,so i guess fans is not the problem with overheating deal,hope it was my thermostat.
 

·
Registered
1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
Joined
·
6,738 Posts
Because they are more prone than any Northstar Cadillac for head gasket failure
 

·
Registered
1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
Joined
·
6,738 Posts
And the engine nipple was clear as well? I would also replace the cooling system pressure cap. If weak the system will boil at a lower temperature.
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #13
that nipple is a metal tube right?if it is, i think it was clear.i did replace the cap already.thanks.
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #14
hi so took my caddy for a ride up hill this morning....it overheated 3 times,somehow i made it back to denver.whats weird is, it overheats and full of antifreeze!its in the shop now i run out of ideas ,c what they say tomorrow!i'll let u all know.it overheats if i go above 3000 rpm's!
 

·
Registered
1926 Model T street rod, 2000 Jaguar XJ8, 1999 Corvette.
Joined
·
6,738 Posts
When you say overheated, to me, that means it boiled over and lost coolant. Sounds to me from what you have written, that the car got warmer than you think is normal as the speed or load increased and did NOT boil over. Most engines running warmer as speed increases means usually a restriction in circulation, i.e. partially plugged radiator, combustion leaking into a cylinder (head gasket) weak pressure cap. We can rule out the cap, we can rule out the purge hose. So again we wait for the diagnosis. Good luck!!
 

·
Registered
eldorado 1998,130000 miles
Joined
·
17 Posts
Discussion Starter #17
so they said its my head gasket....im thinking to try change it myself...what tools do i need to do that job?
 
1 - 17 of 17 Posts
Top