1990 Acura Legend. 2.7 V6. Auto. AC. 210000 km./130000 mi.

LEGENDAGOGO123

MEMBER
1990 ACURA LEGEND

Problem is Chronic-Intermittent Overheating- (to boil-over and coolant loss)
Not related to grade, load or ambient temp.
When overheating occurs-fan(s) do not cycle on.
Observing gauge as temp. Starts to rise - quick application of Auto or AC temp control gets fans operating and restores temp to normal-until next intermittent occurence. This seems to control the situation.

No coolant leaks.
Compression holds.
Pressure tests good.
Radiator re-cored and hoses good.
New radiator cap.
Thermostat and thermosensor - new.
Neither oil or coolant is contaminated.
No loss of coolant.
Completely blocking and restricting air flow to radiator does not trigger condition - remains normal.
Overheating could just as easily occur while coasting down a hill on a cold day ! Is there a sensor or? That speaks to the fans as coolant heats up - perhaps suffering an intermittent glitch?
Thanks for any help you can provide.

One hour of Acura Dealer's Time -Unproductive. Bob

1 Reply

BRUCE HUNT

MECHANIC
3,754 POSTS

I bet you can look at the radiator and it looks good. BUT please don't take it at face value. If you can pressure test the radiator you will know if it leaks. The system must maintain a pressure to perform properly. The pressure in the system raises the boiling point and makes things operate as they should. The radiator can have a slight crack on the top or along the joining to the core. That is my first thought. Radiator cap can be bad and cause issues.

I think there is a second thermostat for the system. The fan should come on to assist.