99 sable overheating

masonjoshl · 06-09-2008, 12:18 PM

Hi, I have a 99 sable DOHC that overheats especially when the AC is on when driving on the highway. it seems to cool down with the AC off and slower speeds. I have replaced the radiator cap, thermostat, water pump, and flushed the system, also made sure the fan is working and nothing blocking the radiator. Produces heat fine (don’t think it’s a clogged heater core) any ideas?

wrench97 · 06-09-2008, 01:51 PM

Does it have 1 fan or 2 some have 1 for the A/C and 1 controlled by a temp sensor in the radiator. Other than that I would have to think radiator.
The heater core would not make any difference. And since you said while highway driving I'd look at the radiator being plugged first.

cardoc · 06-10-2008, 06:18 AM

I agree with the wrench.It sounds like a partially plugged radiator.Once you're moving at a good speed you no longer need the fans,thats one reason they work with sensors.If the radiator is partially plugged it'll be ok at idle but can't handle the demand at speed.

ebackhus · 06-11-2008, 02:56 PM

I also agree with that diagnostic. Running the AC also has a side effect of making the engine run a bit hotter.

06-09-2008, 12:18 PM	#1 (permalink)
masonjoshl Registered User Join Date: Jun 2008 Posts: 1 OS: xp	99 sable overheating Hi, I have a 99 sable DOHC that overheats especially when the AC is on when driving on the highway. it seems to cool down with the AC off and slower speeds. I have replaced the radiator cap, thermostat, water pump, and flushed the system, also made sure the fan is working and nothing blocking the radiator. Produces heat fine (don’t think it’s a clogged heater core) any ideas?

06-09-2008, 01:51 PM	#2 (permalink)
wrench97 Tech Hardware Team Join Date: May 2008 Posts: 3,480 OS: XPSP2	Re: 99 sable overheating Does it have 1 fan or 2 some have 1 for the A/C and 1 controlled by a temp sensor in the radiator. Other than that I would have to think radiator. The heater core would not make any difference. And since you said while highway driving I'd look at the radiator being plugged first.

06-10-2008, 06:18 AM	#3 (permalink)
cardoc Registered User Join Date: Apr 2007 Location: Ct. Posts: 172 OS: win xp sp2	Re: 99 sable overheating I agree with the wrench.It sounds like a partially plugged radiator.Once you're moving at a good speed you no longer need the fans,thats one reason they work with sensors.If the radiator is partially plugged it'll be ok at idle but can't handle the demand at speed.

06-11-2008, 02:56 PM	#4 (permalink)
ebackhus Asst. Manager, Design Join Date: Apr 2005 Location: SATX Posts: 12,732 OS: WinXP Pro SP3 My System Blog Entries: 25	Re: 99 sable overheating I also agree with that diagnostic. Running the AC also has a side effect of making the engine run a bit hotter. __________________ ----------------------------- There are no dumb questions, unless a customer is asking them. Help in the fight against cancer and other serious illnesses.