joeberg
Member
- 42
- 2
- 8
- Location
- Atlanta, GA
I am having an issue I haven't seen before. I have searched and checked the TM's to no avail. I have a 94 M998A1 with a fan that engages every time I rev my engine past a certain point. When it engages at high RPMs, there is a buzzing/vibrating/resonating sound with it that goes away a second or two after engaging or after disengaging when I left off the accelerator. It doesn't make this sound when engaging at lower RPMs. It only makes the noise when engaging at high speed.
If I unplug the TDM, the fan is engaged from the start and is already engaged at high rev and doesn't make the sound. It almost sounds like a resonating or grating sound. I am wondering if it could be the fan clutch slipping because it is engaging at high rev, but my first concern is why it is engaging at high RPMs to begin with. It is engaging regardless of the engine temperature and seems to do it when I hit the same RPM range every time whether I am in neutral or in 3rd gear at about 55mph. I have access to 4 other HMMWVs and none appear to do this. I did have a belt break and have to change the belts a week ago but I honestly don't know if it was doing this prior. Does anyone have any thoughts to what may be happening or what to look for? Thanks in advance!
If I unplug the TDM, the fan is engaged from the start and is already engaged at high rev and doesn't make the sound. It almost sounds like a resonating or grating sound. I am wondering if it could be the fan clutch slipping because it is engaging at high rev, but my first concern is why it is engaging at high RPMs to begin with. It is engaging regardless of the engine temperature and seems to do it when I hit the same RPM range every time whether I am in neutral or in 3rd gear at about 55mph. I have access to 4 other HMMWVs and none appear to do this. I did have a belt break and have to change the belts a week ago but I honestly don't know if it was doing this prior. Does anyone have any thoughts to what may be happening or what to look for? Thanks in advance!