How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike S. Your Own Question
Mike S.
Mike S., ASE Certified Technician
Category: Cadillac
Satisfied Customers: 7081
Experience:  ASE certified
20625509
Type Your Cadillac Question Here...
Mike S. is online now
A new question is answered every 9 seconds

1998 Cadillac Deville over heats when A/C is turned on. Any

Customer Question

1998 Cadillac Deville over heats when A/C is turned on. Any ideas?
Submitted: 11 months ago.
Category: Cadillac
Expert:  Mike S. replied 11 months ago.
Does this have an electric cooling fan? If it does, doe it have 2 and if so, does the one come on automatically when you turn on the ac? if not, that could be your problem.Maybe a relay or a fuse. What engine is in this?
Customer: replied 11 months ago.
engine is 4.6
Also coolant level is fine but inside dash is saying check coolant level (Not sure if it is a bad coolant level sensor?)
Yes when AC is turned on both fans come on... The car coolant temp rises pretty quickly too.
Expert:  Mike S. replied 11 months ago.
Is the engine misfiring or the exhaust blowing out any white smoke like when it has a blown head gasket?If not, I would remove the thermostat and leave it out and see if it overheats now, or just replace it but I would like to be sure first so I would leave it out first. Then if it don't overheat with it out, replace the thermostat.
Customer: replied 11 months ago.
no blown head gasket... I'll check thermostat
Expert:  Mike S. replied 11 months ago.
Once you get it out you can test it on the kitchen stove. Place it in a pot of water and stick in a kitchen thermometer and see if it opens within 5 degrees of what it is rated at.
Customer: replied 11 months ago.
what is normal operating temp?
Expert:  Mike S. replied 11 months ago.
Slightly above 180 f.
Customer: replied 11 months ago.
ok removed thermostat and with A/C running car is running at 244f is that high? Fans are on
Customer: replied 11 months ago.
Temp difference at radiator hoses 170f on one end 120f on other end
Expert:  Mike S. replied 11 months ago.
I would think the water pump isn't moving coolant. Have you changed it?
Customer: replied 11 months ago.
what temp is considered over heating?
Expert:  Mike S. replied 11 months ago.
I would say around 240f but it all depends on if you have anti-freeze in and at what mixture it is because plain water boils at 212f and if you add pressure to it by keeping a good cap on the system then the boiling point goes up a little, then if yo use a mixture of anti-freeze and water, the boiling point goes up even more, so basically anything over 212f and when the water/coolant boils over.

Related Cadillac Questions