Last summer, my the A/C in my car was blowing hot. So long story short, there were a couple of issues. The mechanic found , when he took things apart, engine coolant where it shouldn’t have been, in the heads I think he said. 07 Grand Marquis, V8. So that repair was a grand+.
Apparently whatever is wrong with the heater requires removing pretty much the entire dash to reach, and costs about $600. And probably a day+. So since I was into him already for so much, he offered to just clamp off the heater for me.
This is Arizona, I maybe would use the heater a few mornings, and I betcha’ I would be using the A/C later that same day, so I said yes.
Now the other day I was in hella traffic, probably for 45 min. waiting for an accident to clear. It was hot out. I tried running the A/C, but it was dragging the RPM’s wayyyyyyyyyy down, I could feel it pull hard and I think they dropped to 5.
The temp. gauge went all the way to red light. I pulled off, turned it off, and waited. The temp. gauge was normal in 15 min., I waited another 15 to be sure. No issues since.
Auto parts guy said all looked good to him, coolant was full, and he said it was probably just the traffic backup. But I have been in that kind of traffic before when it was summer here and well over 100 degrees, and it’s never happened before.
Could it be the clamped off heater? Should I just bite the damn bullet?
The car’s cooling system should be able to maintain the engine’s temperature even with the heater clamped off. You have something else going on.
You might have had an air bubble in the coolant that wasn’t properly cleared out when the other work was done. It may have worked its way out on its own when the car overheated. Keep an eye on it though. You might have some other issue like a faulty sensor or some sort of electrical problem that results in the radiator fan not turning on when it should.
Dollars to donuts, your radiator is plugged.
As above.
Or the new head gasket may have failed due to improper installation or undiscovered head warpage from the previous overheating episode. Frustrating when exhaust gasses get blown into the coolant creating “air” bubbles and overheating issues.
Your engine has coolant running through it like blood. It picks up heat from inside the engine and runs it out to the radiator where it is dissipated into the atmosphere. The now cooler coolant returns to the engine for another load of heat. Your interior heater is nothing more or less than an little radiator that dissipates heat into your car’s interior. Coolant is diverted from the primary circulation and through that interior heater. It’s a fairly small amount of juice, but not insignificant–an emergency measure for limping an overheated car is to turn your car’s interior heat on full blast, thereby gaining the benefit of a secondary (smaller) radiator.
Anyhoo, in the situation described in the OP the interior heater isn’t expected to play a meaningful role in cooling the engine any more than your left hand is expected to provide a means for your body to shed excess heat.
- On review, I made an assumption about previous overheating. The “coolant where it shouldn’t have been”, in the heads, is a blown head gasket, which would have been replaced. I assumed the original problem was an overheating event, leading to warped heads, leading to gasket failure. Sorry for the confusion. I still have coffee where it shouldn’t be (in my mug, on the kitchen counter, at home).
You gave us another clue when you said the A/C was dragging down the RPM.s. It was building up too much pressure. It sounds like your fans are not plugged in. Possibly left undone after the work was done on your car. Your over heat symptom also sounds like a fan not operating. I would check and make sure your fans are plugged in.
Fans “plugged in.” Is this what I should say to my mechanic, please double check the fans are plugged in??
No overheating again yet, but still no comfort level as the air is still stupid.
an '07 would likely have long-life coolant, which doesn’t “plug” radiators anymore.
I believe that he was referring to was after the head gaskets were replaced the electric fans were not plugged back in.
Anytime you have an overheat problem when idling for a while it is usually associated with air not passing over your radiator. Same with your A/C, the fans are supposed to cool your condenser and keep the pressure from going up too high. When driving down the road it won't usually present much of a problem.
classic symptoms for a bad fan clutch.
*the fan clutch is a temperature sensitive hydraulic coupler for a belt driven fan.
they get weak when they get older.
I’d said fan clutch, as a friend of mine has Marquis of that vintage that has a belt driven fan. turns out that yours, if it’s a 2007, is the first year of that body style to go to an electric fan.
my bad.
anyway, regarding what to say to your mechanic. he doesn’t need you to diagnose the problem. you probably wouldn’t take it to him if he did. what he needs is a detailed account of the symptoms and then any situation(s) that brought them on. he should be able to take it from there.
Amen, amen, amen.