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1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Wed Apr 06, 2016 3:50 pm
by JonVoit
My 1986 LeBaron, 2.2L Turbo with AC is overheating at idle/traffic but not while driving.

My lead suspect at the point is the cooling fan which doesn't appear to be coming on. Even though I'm pretty sure it was coming on before and would still overheat while at idle/traffic.

I've only had the car for a few months and I already had to have the head replaced due to missed small head gasket issue that turned into a cracked head.

Besides some wrenches I don't have any other tools or equipment, (voltage meters) so I'm wondering is there's any troubleshooting I can due for the fan myself before I have to take it back to the shop for more work ($$).

Thanks,

Tim

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Thu Apr 07, 2016 4:25 pm
by Kwagon2
Hi
You are indeed limited as to what you can check , at the very minimum a few jumper wires with insulated Aligator clips and a Volt meter would be required to do a set of basic checks.
Normally the radiator cooling fan is controlled by the logic module (located passenger side kick panel) via a temp sensor located to the right of the thermostat when facing the engine and a radiator fan relay (located drivers' side shock tower closest to fender). The relay is energized by the module when engine temp is up or when the A/C is selected. Does the fan operate with the A/C on , If it doesn't then the problem could be from the relay down to the fan(not considering problems with the A/C such as low Gas pressure etc.) Replacing the relay is easy and at worst you'll have a spare relay.
You can do a visual of the wiring to the fan and the relay to see if anything is obvious .
If you check the front of the engine around the driver's side near the cylinder head you'll see a number of ring terminals that have wires attached and disappear into the harness , these are grounds and should be clean and tight as one of them is the ground for the cooling fan.
If you think the fan is still operating and the engine is overheating you may have a restricted cooling system requiring a flush and chemical cleaning etc.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Fri Apr 08, 2016 5:14 am
by JonVoit
Great info Kwagon, thanks. Especially around the relay location and ease of replacement, because that's my new lead suspect.

Today I disconnected the temp sensor and the fan comes on, so the fan is good.

I spoke with a mechanic after finding out that the fan is still good, and he also suggested the relay as well as a fan fuse, however I can't find any information on the internet about a fan fuse, so maybe he was mistaken in that?

Since I don't have a volt meter I'm just going to replace the relay and hope that does the trick, or I'll have a spare as you say.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Fri Apr 08, 2016 2:20 pm
by Kwagon2
Hi
If you disconnected the temp sensor and the fan started then the whole show is OK as the logic module starts the fan using the relay! As I mentioned it should also start and run when the A/C is selected for operation. Disconnecting the temp sensor should have given you a fault code as well. (code 22)
There is no fuse for the fan circuit ,(hasn't been since '82) its protected by a fusible link (a hypalon rubber covered calibrated wire in the harness located driver's side front fender area ). That appears to be OK as well .
So unless the temp sensor is out of calibration (quite possible) and not starting the fan at the correct temps you may have a slight radiator problem.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Sat Apr 09, 2016 2:18 am
by JonVoit
Great info, and it makes total sense too. Thank you!

When the temp sensor is unplugged that sends a message through everything (computer, relay, fan), and the fan comes on, then everything must be good from there down. This now has me concerned about my mechanic though, because I told him about the fan coming on when the sensor was disconnected and he suggested checking the relay. :shock:

I tried turning on the AC before, and that didn't make the fan come on, but I tried again today, and it turns out it does come on, after about a minute, and then it shut off again, and then after a bit it came on again for about 20 seconds then off again.

Is that normal? I did some interneting about intermittent fans and there were a lot of references to electrical shorts, and they sound hard to find. Basically have to test each section at a time to narrow it down, then try to find the exact location of the bad wire/connection.

I'd like to see the fan kick in properly before I give up and take it to my now questionable mechanic. You mention that the sensor could need calibration. Would just replacing it do the trick? That's something I can do at they only cost $10.

So in summary.. if you don't mind... intermittent fan when AC is on normal or not? (sounds like not) and is swapping out the temp sensor worth trying?

Thanks!

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Sun Apr 10, 2016 3:11 am
by Kwagon2
Hi
Ok, well the intermittent fan operation on A/C is not normal the fan should be on continuously while the A/C is selected ...
there are a number of other factors in play here too. There are three additional switches/relays in the A/C fan circuit Refrigerant low pressure , Compressor thermal switch and the WOT relay (wide open throttle) if any of those are defective or are operating then the fan would cut out, in addition to the compressor, so keep an eye on the compressor if its clutch is energized and quits at the same time as the fan then its an A/C control problem. Personally I would look at the Refrigerant low pressure switch. Located at the firewall passenger side on the Thermostatic expansion valve module, its a two terminal switch .
When I mentioned the sensor Calibration I should have said "defective" as they cannot be recalibrated. ..just replaced, so yes a replacement would be a good thing to try.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Mon Apr 11, 2016 5:24 pm
by K-CAR_WAGON
I suspect that the refrigerant pressure is low and the low pressure cutoff switch is working normally to cutoff the A/C after a short try to prevent compressor damage.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Tue Apr 12, 2016 12:12 am
by JonVoit
Thanks for all the insight here. The AC has never ran cool so I'm sure there's no refrigerant, meaning low/no pressure like Wagon suggests?

I tried to replace the coolant sensor but the old one wouldn't budge so I couldn't get it out. Plus after I disconnected the sensor to test the fan the car started to have a hard time starting up, even after reconnecting the sensor,and now it won't turnover at all. Just keeps cranking.

Put together I'm throwing in the towel and taking it to the mechanic. I'll update the thread with what happens.

Thanks for the help!

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Fri Apr 15, 2016 10:24 pm
by JonVoit
So it looks like we found out what the problem was...

Nothing.

The fan does work, it just doesn't come on until the temperature gauge gets to two bars above the middle (a bit below 3/4), and then the temperature drops back down to the middle. I was just too paranoid about another blown gasket to let it stay at that level on the gauge, so I never let the fan do it's thing.

The temperature reading on the thermostat housing when the fan kicks on is 218, and from what I've found in this forum, and others, is that is OK. It would be great if someone could confirm that though, because it seems a bit high.

The lesson learned here is to determine the temperatures first, before thinking something is wrong.

The problem starting turned out to be related to the distributor. It must have just happened to go bad at the same time as I was doing all the fan fixes.

Re: 1986 2.2L Turbo Cooling Fan and Overheating Problems

PostPosted: Sat Apr 16, 2016 2:04 pm
by Kwagon2
Hi
Here I'm thinking major overheating...ie:gauge pinned reserve tank filling etc. But all is well that ends well....
I don't have the actual '86 specs but with regards to temps, the radiator mounted fan switches used prior to '85 were/are calibrated to start the fan at about 208 Degrees F so you're good since you're reading the temp from outside the engine. If you're gauge is dancing around the middle that confirms it as the middle mark is where even the owners manual tells you your gauge should be operating.
From the start of the emissions years Chrysler always ran their engines hotter than most and they continued that trend into the four cylinder years. Opening a hood on a mid seventies Big block Chrysler with Air and the hood insulator pad always rewarded the person opening the hood with a major waft of pretty hot air yet the gauge said "all is well".
So have fun with your LeBaron...