Electric cooling fans

ConnieMarie · #1 (**permalink**) 07-30-09, 07:44 PM

I spent some time on here last night researching my cooling problems. I was wondering if any knows which fan is the primary on the 95 Deville. There's no exhaust gas coming into my coolant resevoir (plastic). I occasionally get a boil over out of the resevoir. I flushed the system, that didn't help... so last night (after it cooled down to about 95 lol) I went out and pulled the resevoir again...cleaned it..replaced the hose and radiator cap. Went out today and ran the car for while with a/c on. Mind you it's over 100 degrees out so it doesn't take long to heat up lol. The front fan turned on after I turned the a/c on. The rear fan never turned on. does someone know where the wiring connector is on the rear fan so I can test it? Can't find it (yet). The radiator did bubble a little into the holding tank...not near as much as it did before. Also, does the fan run after the car is turned off?

If there's already a thread on this sorry for posting another. I just couldn't find it for my 95 4.9

thanks!

**Ranger** · #2 (**permalink**) 07-30-09, 09:24 PM

4.9's are not known for head gasket problems. Have you tried replacing the thermostat? Maybe it's sticking. Might also try flushing the radiator. I thought both fans where on the inside (pullers). You have a pusher and a puller? Also have the cap checked to be sure that it holds pressure.

ConnieMarie · #3 (**permalink**) 07-30-09, 11:19 PM

Thanks Ranger! I have done all that twice now. We have owned the car for eight years. Only doing this when we pull mountains here in Oregon in the heat. Thank God it's pretty cool most of the time here. It does have a pusher and a puller btw. I went out and was checking for the wiring to the rear fan..couldn't find it. Searched all over...finally looked at the front fan...realized it was plugged fight below the fan motor. So I went searching again. Found the plug..wrapped ever so nicely around another components wiring..un hooked. no wonder I couldn't find it! It was my mother in-laws car before we had it. She had the lifetime oil change etc...well....all these years it's been unhooked. The way it was wrapped it had to have been done on purpose. The only people that worked on it was the dealer in Medford. Everytime she would take it in for an oil change or other service..they would always find something wrong with it, charging them lots of money. I'm wondering if this was done on purpose. I took it out and had the A/c on full blast...ran up and over several passes and back...the engine was good and hot..and it's still in the 90's out. Funny it didn't bubble once when I turned it off!

WOOHOOOOOO!!!!

ps ...I do feel a little ignorant that I didn't find this after all these years...but glad i did before something terrible happened.

ConnieMarie · #4 (**permalink**) 07-30-09, 11:22 PM

Oh one other thing..I have a wierd Deville...I have all the paperwork from when my mother in-law bought it...window stickers too. It is a Deville, with all the top notch add ons..4.9 v8, but three pieces of paper work say it's a concours...wierd or what? LOL i always have had offbeat cars and trucks.

**Ranger** · #5 (**permalink**) 07-30-09, 11:59 PM

That IS strange. Keep an aye on it for a while.

I had a '92 and can't remember the fan configuration.

00 Deville · #6 (**permalink**) 07-31-09, 12:06 AM

Quote:

Originally Posted by ConnieMarie

Oh one other thing..I have a wierd Deville...I have all the paperwork from when my mother in-law bought it...window stickers too. It is a Deville, with all the top notch add ons..4.9 v8, but three pieces of paper work say it's a concours...wierd or what? LOL i always have had offbeat cars and trucks.

The top-of-the-line version of the 1995 DeVille is called a Deville Concours.

ConnieMarie · #7 (**permalink**) 07-31-09, 03:36 AM

but the Concours has the northstar in it in 95...not the 4.9...that's the weird thing.

**Ranger** · #8 (**permalink**) 07-31-09, 09:57 AM

That IS weird.

submariner409 · #9 (**permalink**) 07-31-09, 12:14 PM

That aftermarket fan was installed for some obscure reason which leads me to believe that the original problem is still there.

A dead fan behind the radiator is a significant airflow restriction. Does the front fan run all the time, A/C on or off ? If so, something's very wrong.

Most of the FWD cooling systems (don't know about the 4.9) use 2 fans in a mount behind the radiator - no pushers. The fans run in slow whenever the A/C is commanded ON and when the engine temperature gets to about 224. The fans go to fast at 236.

The thermostat is set to begin opening at 188 and to be fully open at 206, so the FWD's normally run with the thermostat open about 66% because the cooling system is very efficient. The coolant tank should be half full, COLD. Any more is overfilled. The airspace is there to allow coolant expansion and contraction with varying temperature. A 50/50 mix of coolant/distilled water boils at 218 degrees at atmospheric pressure and 265 at 16 psi. A 70/30 mix (GM recommended maximum concentration) boils at 276 degrees/16 psi.

**Ranger** · #10 (**permalink**) 07-31-09, 02:17 PM

Now THAT make sense. One fan is an add on. No wonder I can't remember it. If you've had the car for 8 years and it has always done it on a hill climb in hot weather, it can't be a head gasket. It would have put you out of service many years ago. I'd go back and look at the basics. Belt tensioner, cap holding pressure, get rid of the restrictive after market fan, flush the radiator.