: 1994 Eldorado Thermostat



joylynn7777
01-29-10, 04:40 PM
Please, could someone tell me exactly where the thermostat is located on a Northstar engine in a 1994 Eldorado. Please use layman's terms as I am a woman who knows enough about cars to not be afraid to attempt the fix myself, but not techinical enough to know better...lol

cl1986
01-29-10, 06:11 PM
Well first, can i ask why you think it needs a thermostat? It might need one but very often its not the cause of symtoms that would look like a bad thermostat.

anyhow, its located at the rear of the engine, so drivers side on that coolant hose that goes to the lower radiator fitting, theres a neck there with 2 10mm(wrench size) bolts that hold that neck on. The only thing is when if you pull that off, it will leak coolant all over the ABS module and can cause a $500 repair. Cover the ABS unit (pretty easy to figure out since it has ABS stamped on it) with a plastic bag or something, i even use a defletor as well to keep most of the water off the bag.

Other things you might want to look into first are the purge line at the coolant tank, very small 3/8" line thats about 4" long, has 90* elboe in it, take it off at the coolant tank side and make sure you can blow through it, if not it can cause cooling problems.

Theres many other things that may cause cooling problems including head gaskets. I would try to figure out whats wrong before replacing any parts.

joylynn7777
01-29-10, 06:44 PM
Since the radiator has been replaced along with the top hose and when you look into the resevoir there isn't any "flow" going on, I kind of figured that the thermostat is stuck closed.

Krashed989
01-29-10, 08:04 PM
The reservoir shouldn't have any visible flow through it....

Maybe the purge line is clogged as suggested before. If the purge line is clogged then any air that may be trapped in the system will not have a way out, which would basically impede flow and make the car overheat. Just do this simple test; Disconnect the small line from the top corner of the reservoir (not the one under the cap) and start the engine. Coolant should trickle out of it. If it doesn't then it is clogged somewhere.

joylynn7777
01-29-10, 08:41 PM
Thank you both for such detailed information. I greatly appreciate it. I will let you know tomorrow afternoon what I found out.

Ranger
01-29-10, 10:30 PM
Since the radiator has been replaced along with the top hose and when you look into the resevoir there isn't any "flow" going on, I kind of figured that the thermostat is stuck closed.
If the thermostat was stuck closed, you'd overheat. If not seeing any flow is your only "symptom", you're looking for a boogieman. There ain't none and everything is normal. Enjoy the ride.

joylynn7777
01-29-10, 10:41 PM
Yes, I started to overheat and along with the other symptom, that was what I came up with was the thermostat. I just wish that it was easier said than done sometimes...alas the good old days of a slant six.

Ranger
01-29-10, 10:48 PM
Oh boy. Tell me about the overheating. How often? Under what conditions? How bad does it overheat? Are you using coolant? Do you have an external leak? Does your exhaust steam more than normal?

Ranger
01-29-10, 11:00 PM
Yes, I started to overheat and along with the other symptom, that was what I came up with was the thermostat. I just wish that it was easier said than done sometimes...alas the good old days of a slant six.
Careful, you're aging yourself.

joylynn7777
01-29-10, 11:17 PM
Yes, I know that I am aging myself, no worries though. I have ruled out the head gasket as that has happened before to me and that one is definitely smoke out of exhaust, but there is hardly any at all. Also, no water in the oil. But I do think that I have a leak somewhere it is just that no one can find it anywhere. Under a pressure test earlier in the fall I didn't lose anything. I am at my wits end though. If it isn't the thermostat, then I will have to give up, sell it as best I can and buy a different car. Economy has my income down 44%...that is why I am doing this myself.

Ranger
01-29-10, 11:28 PM
I have ruled out the head gasket as that has happened before to me and that one is definitely smoke out of exhaust, but there is hardly any at all.
I assume you mean on a different car. In it's early stages it won't steam very much and the Northstar will almost never put coolant in the oil. Do yourself a favor before you start throwing parts at it. Rent a block test kit from Autozone or another parts store that has a tool rental program. You may have to buy the solution. Worst case, by the kit from Napa for $50. Follow the instructions and test the air above the coolant in the surge tank. That should tell you if it is the head gasket or not and then you can go from there.

cl1986
01-30-10, 12:31 PM
not sounding very good, do the block test, which isnt really a block test they just call the tool that. It checks for exhaust gases in the coolant, fluid will turn yellow if its bad, happened on my sls

these engine runs great even with head gaskets out, mine was running awesome, loosing coolant like crazy though. It only uses coolant while running, i thought it would leak into the cylinder and hydrolock it but it never did.

joylynn7777
01-31-10, 08:37 PM
Well, it isn't the thermostat, not the head gasket, nor are any hoses blocked. The cooling fan isn't coming on at high temp when it should. Checked the fuse and to see if it was rotating freely both are fine, so now what? I am at a total loss, should there be some sort of switch somewhere that I can replace? By the way thanks for all of your help, thermostat was easy to replace.

Ranger
01-31-10, 10:21 PM
I think there are 3 relays between the fans.

Have you confirmed flow from the purge line?

joylynn7777
01-31-10, 10:34 PM
Yes it is clear as a bell...free flow, if you are talking about the rubber part, if you are talking about the metal part I didn't check that...I do know that the fan isn't coming on at all. WWhere exactly are the relays located? Thanks

cl1986
01-31-10, 10:41 PM
the main fan has a very accesable electrical connector at the lower portion of the fan, check for voltage there. THe small fan has a PITA connector on it.

I just pulled my fan out of my eldo cause it was toast......

Not sure which relay, but there are 4 big relays under the fuse panel cover on the drivers side in the engine bay, they are hdden under all the large fuses next to the washer fluid tank.

joylynn7777
01-31-10, 11:34 PM
ok, I will look at these tomorrow morning and see what is up with those, also if I have to replace the fan, shat is the cost on that.