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Ask sprinkles08 Your Own Question
sprinkles08, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 21410
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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Engine coolant overheating which of course the engine

Customer Question

engine coolant overheating which of course the engine overheats. engine has super compression runs exceptionly well but I'm experiencing overheating problems. I'm not sure if an engine coolant temp sensor being bad would cause the overheating issue
JA: Have you checked the connectors on the sensor itself? It's important that they not be loose or corroded.
Customer: no cant say that ive checked them as of yet. I noticed tht the cooling fans but activate as soon as I iniate or turn on ac orr defog switch
JA: What is the model/year of your Cadillac?
Customer: 1999 Cadillac deville d'elegance northstar engine
JA: Are you fixing your DeVille yourself? What have you tried so far?
Customer: yes! I'm self proclaimed technician(school trained)ive replaced radiator haven't really replace any other cooling system components yet.
JA: Anything else you want the mechanic to know before I connect you?
Customer: ion think that I'm having head gasket issues bcuz the car runs as if its new except overheats I'm aware that this particular caddy had design problem with the head bolts being too shallow or not threaded deep enough into the block but the engine compression is really super nd the engine seems to have exceptional power
Submitted: 1 month ago.
Category: Cadillac
Expert:  david craig replied 1 month ago.

Hi Im David, thanks for visiting the site. do you notice if the cooling fan activates once the temp hits a tad over mid gauge? (without the ac on).

Customer: replied 1 month ago.
it activates as soon as I turn ac on
Expert:  david craig replied 1 month ago.

not asking that. with the ac off. when does the cooling fan activate?

Customer: replied 1 month ago.
about mid guage
Expert:  david craig replied 1 month ago.

ok. have you been having to add coolant?

Customer: replied 1 month ago.
no coolant level remains adequate even lost some thru the resevior overflow tube
Expert:  david craig replied 1 month ago.

ok. when was the last time the thermostat was replaced?

Customer: replied 1 month ago.
maybe bit over year nd a half
Expert:  david craig replied 1 month ago.

ok. now with the car cooled down. start it up and let it run after a few minutes (up to 10), check the upper radiator hose to see if its hot.

Customer: replied 1 month ago.
the upper hose did get awful hot
Customer: replied 1 month ago.
thanks this isn't workin to good for me at this time.
Expert:  david craig replied 1 month ago.

how about the lower hose

Expert:  david craig replied 1 month ago.

what do you mean its not working to good for you?

Customer: replied 1 month ago.
never really checked lower hose. I meant I'm needin to take off. iwill get back to yall later
Expert:  david craig replied 1 month ago.


Customer: replied 1 month ago.
Expert:  david craig replied 1 month ago.

you bet

Expert:  david craig replied 28 days ago.

checking in to see how its going

Expert:  sprinkles08 replied 25 days ago.

Hello and welcome to JustAnswer!

There are several things that will cause overheating. You could have a bad water pump, thermostat, a cooling fan issue, a combustion leak into the cooling system, and it's possible that the radiator is restricted if it wasn't replaced after this problem started. You mentioned replacing a radiator but I'm unclear whether it was on this vehicle and when.

Does it use any coolant, run rough or smoke from the tailpipe?