Weird readings from new fan clutch.

[JayArr]

So, I got everything back together today. New radiator, water pump, thermostat, hoses and fan clutch. The transmission cooler is also installed.

I tested the cooling system at 15 pounds and it held for 30 minutes. I also did leakdown tests and none of them leaked to the cooling system.

I start it up and it runs like a champ, started first time, purrs like a kitten. I spend ten minutes adding transmission fluid and check the gauge and it's not even 1/4. So I rev it up a bit and then leave it for another ten minutes and it is still not half way. Now, this is a good thing, it means that the parts I installed have made a difference but it also means the thermostat doesn't open at idle.

I grab my tech2 and jump in and rev it up to 1500RPM and hold it there until the thermo opens to try to make sure I purge any airpockets.

While I'm hooked up I figure I should check the new fan clutch and the first thing I notice is that it's way too high at idle, 704RPM when desired is 304.

Next I go to the screen where I can change the command to the clutch, I set it at 100% and reve the engine to 1500 and the desired is 2512 but I only get 1472 out of the clutch.

With the old clutch it would adjust to the desired RPM but this one seems to run too fast at idle and too slow at higher RPMs.

Is this a bad clutch right from the factory?

Purchased from Rock Auto, it's a Hayden.

Can anyone think of a reason not to ask Rock Auto for a replacement?

 

[Mooseman]

How much time did you give it between commanded speed changes? It does take a bit of time for the silicone fluid to move from the reservoir to the clutch. And since this is a fluid type clutch, I don't think it can be controlled with any kind of precision. The PCM probably has a parameter of how much off the commanded speed has to be before it throws a code and from what I can tell, it's pretty wide.

Maybe being new it needs to break in a bit? A little more speed at idle isn't a bad thing for me except maybe a little more fuel being used. A/C and aux tranny cooler would benefit from more air movement.

As a side note, I had recently noticed that the ACDelco had dropped in price but now I can't find it on RA. However, the Mahle/Clevite, which is made by Behr, the original OEM, is only about $20 more.

 

[JayArr]

I agree, a little more speed at idle wouldn't be bad but that's not supposed to be how it works and it cost a lot of $$ so I want one that works. If it is not built right I want to return it right away before my warranty period with RA expires.

It had been running for 30 minutes, I would hope that is enough to "break it in" so I don't see that as a factor.

RA has accepted the return, they are sending out a new one and then I can return this one. I can drive it in the meantime.

 

[JayArr]

The GM one is there for me, $306. The Haydon was $166.

I'm trying to return the Hayden for store credit so I can by the Behr but I don't have the original box so I don't know if they'll accept it.


Could someone with a Tech2 do me the favour of hooking up and idling their vehicle with it attached and tell me what the actual and desired fan speed are? It's in the live data section under Engine Data 3, entry 25/26.

 

[TJBaker57]

I must point out that anyone with an elm obd adapter can also check the desired and actual fan speeds. The pids are available here in the scanners section.

Also, I once saw a GM service TSB or the like that stated that if the fan speed at idle was not greater than 800 they didn't consider that an error. Or some wording to that effect. It was one of those threshold values in a flow chart.



Edit: my clutch fan is a junkyard pull. Both it and the original it replaced seldom went below 700 at idle but both of them got their full speed almost immediately when commanded. I think I worked out the full speed to be about 1.2 times the engine rpm? Not sure I remember the ratio right though

 

[JayArr]

My new Hayden won't go up to speed, it lags by more than 1000RPM at different test RPMs. I'm going to buy the Behr.