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Fan runs very often

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Hey guys I am working on a 05 F550 with a 6.0 and torqueshift. This truck has succumb to pretty much every common 6.0 problem that has ever existed several times. Had a new engine installed 60,000 miles ago and a set of head gaskets probably less than 10,000 miles ago. Now that we have some background here is the concern. The engine fan runs very often, even when it should not need to run. For ex. outside air temp is -15F with a 10mph head wind, with wind chills about -30F(no winterfront). The fan will turn on full speed and run for up to a minute, and do this every 5 minutes or so. I hooked up the scan tool and monitored while the other tech with me was driving. The engine oil and coolant temp differential is about 7 degrees. The thing I found interesting is that the engine oil temp is running around 220 degrees and the coolant temp is about 215-222 degrees. This seems very warm to me, I would think it should run around 200. I am wondering if we have a front cover that is cavitated and causing the water pump to be inefficient. Has anybody ever measured water pump pressure on a 6.0 before, is this a worthwhile test? Or is a guy better off to just remove the water pump. We have blown out the cooling package with air and than pressure washed. The coolant is a 50/50 mix that tests at -35 and the SCA is ok. According to the information I have been able to find regarding the fan(in the workshop manual, PCED, and bruces book) everything is correct. I have driven another truck like it the only difference is that it is an 06'under the same conditions and the fan never ran once that day. The operator also told me that he hardly ever heard the fan for the first 30-40,000 miles and it has been running more often and longer as time goes on. Sorry for the long post guys but wanted to give all the information that I have. Thanks

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Running 215-222 ECT is your problem, it should be running under 200F in -15F ambient. Fix that and your fan cycling problem will be fixed. Possible problems include all the regular suspects- bad stat, clogged radiator, someone left a rag inside, etc. A cavitated cover is barely on my top ten list. I'd probably double check the temp at the sender with an IR gun, hang a new OE stat in it, and if that didn't fix it, I'd do a cooling system flow test. Does it have any coolant usage complaint? A cooling system pressure test on a road test might not be a bad idea. Look around the shop and see if you have one of these by chance:

 

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This cooling system flow tester tool would identify a (badly) cavitated cover, cavitated pump, blockage, loose impeller, cure ED and baldness.

 

If you can't find a flow tester you're going to diagnose it using caveman methods- pull the WP and inspect, pull the rad and flow it with a garden hose, etc. I'm thinking this problem is linked to the real reason it needed a motor and head gaskets.

 

Good Luck!

 

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Wasn't there some problems with reman engines and water pump impellers, overheating, engine failures, and the like?

 

I think Mike Chan had one of these, where the impeller fell off the water pump.

 

And I agree with the high engine temps being the fan issue, I think I have seen the fan clutch come on between 214-218 degrees EOT.

 

We're right around 0C/32F here, and driving a truck with 4.30 gears in MLP range '3' at 3200rpm for about 5 minutes only got me ~196 ECT and ~210-213 EOT, I didn't even hear the fan come on.

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Wasn't there some problems with reman engines and water pump impellers, overheating, engine failures, and the like?

 

I think Mike Chan had one of these, where the impeller fell off the water pump.

 

And I agree with the high engine temps being the fan issue, I think I have seen the fan clutch come on between 214-218 degrees EOT.

 

We're right around 0C/32F here, and driving a truck with 4.30 gears in MLP range '3' at 3200rpm for about 5 minutes only got me ~196 ECT and ~210-213 EOT, I didn't even hear the fan come on.

LOL. Yup Aaron, you remembered didn't you? That particular truck was an '03 that racked up about 80,000 kms. (50,000 miles) after the reman engine installation before it came in with the water pump impeller shot.

 

If you want to try something quick, you can disconnect hose from the intake manifold to the degas bottle, at the bottle. Start the engine to check for coolant exiting the hose. If you see coolant exiting right away, in a good steady flow, then the water pump is working as it should.

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What Dwayne said... not too many years ago there was a big kerfuffle here in Gods country that got head gaskets at least once and finally, out of desparation I suppose, the owner drove it to destruction (I think we might have enven mentioned it in one thread on here)..

 

The rad was wearing a real nice "fur coat"...

 

FWIW, you have to look directly at the front of the rad like Dwayne said.... leaves, dust, grass, seed, fur, hair, small mammals and most kinds of flying insects can make it through ever other layer of the cooling stack except the rad... And they will hide there until it is time to offer up a life altering event...

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Mayhaps I should start a "word of the day" column? Can you boys and girls say cunnilingus (George Carlin called it "yodeling in the gully")? Fellatio? Felching (where the fuck did that shit come from?).

 

Hmmmmmm maybe we should stick with words like "cam phaser", low/reverse clutch" and "Montreal smoked meat on medium rye bread with Keens hot mustard and a hot banana pepper pickle". Shit... now I'm hungry.

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Tech that drives it had pulled the cooling stack apart, blew it out and than pressure washed it recently. Service manager opted to send it next door because we are really busy at the shop. They replaced the thermostat and said now it will only get to 209. Will give it a try and see how it does. Thanks for all the thoughts on the issue guys. If it doesnt fix it will try to measure coolant flow.

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209 is still awful hot for your ambient temperature...

 

I know it's a 6.4, but my truck won't even hit 209 with the grille cover on, in regeneration, in temperatures that aren't as cold as yours.

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I think 209 is still kind of high. The tech driving the truck, and the dealer are satisfied that it is ok. Some day when I have some time I think I might do some troubleshooting of my own and see if we cant get the temp down where it belongs and make sure the sensors are reading correctly. Thanks for all the ideas guys, I appreciate it.

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