High speed fan operation

[SheeB]

So recently I heard what sounds like the radiator fan operating randomly on high speed while driving. I has a distinct cut in and cut out for about 10 seconds long. Sounds like a plane under the hood almost. Car is not overheating, it's too cold here still for any a/c operation (below 0C), no check engine light. I brought the car to the local garage and they did a health check report on their Snap On tool nothing in history either.

I would like to possibly try driving again at highway speed when this seem to typically happen and somehow be able to manually switch on the high speed fan to see if indeed this is the sound I am hearing. Is there a way I can do this or do I need GDS2? The local garage with the Snap On wasn't sure if he could do this on his tool but he ran out of time to diagnose further.

Any insight on this weird issue?

 

[Moonwink]

How did this turn out for you?

 

[SheeB]

So, just had my neighbor who's son has GDS2. He annually turned on the fans through varied speeds and ta not the sound I am hearing . I'm at a loss.

Maybe something leaking in the turbo piping or something with pcv system venting into the intake? It's just so random.

 

[PoManNox]

So, just had my neighbor who's son has GDS2. He annually turned on the fans through varied speeds and ta not the sound I am hearing . I'm at a loss.

Maybe something leaking in the turbo piping or something with pcv system venting into the intake? It's just so random.

That is a weird one indeed.

Generally any disruptions in charge air flow, as in leaks in the connections or a blown out charge air cooler, will result in limp mode instantly a check engine light and a bunch of codes. These little 1.5Ts will not tolerate any MAF or MAP oddities

Is there a specific speed or gear that makes it happen?

How many miles on it? Could it be a failing vacuum pump?

 

[SheeB]

No check engine light. No limp mode. Nothing in history. Vacuum pump was replaced as a maintenance item at 180K kms. Wastegate actuator replaced around same time. Car has currently 218K kms on it. We live in the country and put the mileage on. Lol.

 

[PoManNox]

No check engine light. No limp mode. Nothing in history. Vacuum pump was replaced as a maintenance item at 180K kms. Wastegate actuator replaced around same time. Car has currently 218K kms on it. We live in the country and put the mileage on. Lol.

I had to do the yankee conversion to ~135K miles! LOL! That's quite a bit. We don't have many higher mileage LYX 1.5T folks reporting anything, so it's good to know.

Could this noise be a wheel bearing or vibrating plastic/rubber? Is the charge air cooler original? It would be near impossible to have a leak there and not immediate issues though.

 

[SheeB]

Sorry yes I'm in Canada. I should've done the conversion. I've not replaced any parts aside from maintenance like spark plugs, air filter, oil changes, tires and brakes. Nothing replaced in regard to the CAC system.

I'll try and take a peek more intensively when I get a chance to borrow the father-in-law's hoist.

 

[Moonwink]

I friend of mine with a late model Chevy Tahoe had the same high speed fan problem fixed this morning at a shop that replaced the thermostat housing (which I suppose included a new thermostat and sensor) to fix the issue.