engine and drivetrain Fan Hitting Radiator (Kinda Long)

[Kile Brekke]

Hello,

 

Last year, I had a somewhat moderate collision with a guard rail that caused some damage on the driver side corner. It wasn't a hard hit, more of an abrasive bounce at ~15 degree angle.

 

It was, however, a hard enough hit to move the engine forward on impact and kiss the fan on the radiator.

It chipped the fan in a couple spots, but I was able to drive it home with no more fan rubbing.

I have been driving it as is for a year with no problems.

 

Now I am having the rubbing problem again after having the car serviced recently.

The service I had done was remounting/rebuilding and reinstalling the correct shifter mechanism on my 5-speed that has been loose for years. The shop put in new bushes and the the correct bar that connects to the tunnel. It works beautifully now and shifting is super easy.

 

I was notified during that install that the drive-shaft/transmission/rear-end could be, and should be aligned better.

I approved the work and it was done. I have almost no vibration cruising down the freeway, its great…

 

BUT, When I picked up the car and got home I noticed that the fan was hitting the radiator again and has chewed up the radiator pretty bad and the fan is far more chipped than before.

It hits a bit when braking and hits really bad when coming to an "emergency stop" (San Francisco traffic)

 

My question is, why is my fan so close to the radiator?

Could my accident have pushed the engine up toward the nose, or is my nose indeed pushed in more than I think? Is that even possible?

Roughly, how much clearance should there be for a correct fit?

 

I am wondering if the shop made some adjustments on the transmission mounts that has actually pushed the engine forward just a touch.

 

Does anyone have any thoughts or ideas on how to rectify this?

 

I appreciate the help.

Edited January 13, 2014 by kile brekke

[scoyote]

Have you got the limiter bracket on your right side motor mount?  This stops the sudden forward  thrust of the engine. The other contributor would be the trans mount---but you have had work done in the area and they would have picked up on a worn mount-----scoyote

[schoir]

Kile:

 

Is the fan rubbing/chewing up the radiator evenly (all around) or is the fan only rubbing on the top 50% of the radiator or only on the bottom 50% of the radiator?

 

Regards, Maurice.

[PaulTWinterton]

+1 on transmission mount.

 

Minimal height adjustment of this mount will cause the fan to hit the rad.  Maybe they changed the rubber to a larger size, tipping the motor forward.  Or maybe it's just loose.  Hope it's that simple.

 

Good luck.

[pilotnbr1]

You could switch over to an electric pusher fan... This is just treating the symptom and not the problem though.. Good luck!

[Mike Self]

Coupla thoughts...

 

Motor mounts do go bad, and the older they are, the softer they get.  Soft mounts will allow the whole drivetrain to shift forward under hard braking, allowing the fan to kiss the radiator.

 

Did the shop install a new tranny mount?  If so, did they use the larger one from either an E21 or a Bavaria?  They are considerably stiffer than the original 2002 mount, and will help keep the drivetrain in place under hard braking.  

 

Did you check the left side motor mount?  The ear (part of the subframe) that holds the mount is a known failure point--it can crack and allow excessive engine movement--and when it breaks, then you have a real problem (and immediate need for a new radiator).

 

Since your car was involved in a little front end fender bender, it would be instructive to measure the distance from the radiator support sheet metal directly above the right, then the left side of the radiator's top tank.  That figure should be the same left or right.  If not, the front end is still tweaked--and the radiator-to-fan clearance is minimal at best, so it doesn't take much tweaking to make 'em meet. 

 

And second the motion about the limiter bracket that's part of the right side motor mount.  Make sure it's adjusted so as to minimize the engine's forward movement--it's kinda intuitive when you look at it.

 

Hope it's something easy, but it has to be connected with what the shop did...

 

mike

Edited January 13, 2014 by mike

[Kile Brekke]

Thanks for the feedback guys.

I'll check the limiter bracket and the left 'ear' for any cracks.

I will also take a photo of the partial rub and upload it FWIW. I believe it is just in one area, about 2-3 o'clock on the radiator.

 

I am not sure what mounts were used on the transmission. I am sure I can check the parts list. The 5 speed was put in before I purchased the car, and I do recall the shop telling me it could have been done cleaner the first time. Hinting at the idea that it may have been a sloppy install the first time. Perhaps their adjustments to make it 'right' was just enough change to set everything off.

[schoir]

Rubbing only (or more deeply) at the 2 or 3 o'clock position might be another clue that the motor mount bracket on the right side is not the "limiter" type or that it's loose.  That would allow the right side of the engine to cock forward and then cause the fan to hit  the radiator in that location.  The fact that it's one of the upper quadrants might also indicate a taller than normal transmission mount (or washers elevating it).

 

Regards, Maurice.

[M3M3M3]

either the engine is moving closer to the rad or the rad has moved closer to the engine, or both. so..check for front end damage and check your engine mounts. they do get old and soft after they have been soaking in oil leaks for 40 years.

for some light reading, type "fan hit radiator" into the search box. many threads on this issue.

[Kile Brekke]

I still have to measure the distance from the radiator wall on either side to determine if there is indeed a shift in the body.

I have not been able to see the motor mounts in detail just yet. I plan on getting in there tomorrow. There has been substantial oil leaks over the years so the mounts are/were pretty wet.

 

I am attaching two photos of the fan position as it sits now. It is definitely hitting in one main region 12- 3 o'clock on the radiator. 

I also took a top side photo which clearly shows an angle where the fan is closer to the radiator.

The odd thing here is that the driver side nose is where the impact took place, yet the fan seems closer on the passenger side?

 

I need to check the limiter bracket, this is the first I have heard of such bracket. I scanned a page from my blue book.

Is the bracket adjustment notated as callout "A" ?

 

Thanks for all your help.

 

[schoir]

That adjustment distance is indeed "A" in the photo from the manual, 3rd from the top of your manual photos and it should be 3mm.

 

The photo that you took from above clearly shows that the engine is slightly cocked to the left, so either your right side motor mount is flush against the limiter or you have one of the motor mounts without the stop limiter.

 

Regards, Maurice.

[DRedman]

While you're checking things, and if you have the type of mount shown for the left hand mount you need to replace it with the newer type (rectangular vs round)which is much stronger.

[Kile Brekke]

Hello,

 

I just wanted to update some findings on this and a source of my issue.

 

The mounts themselves do not appear to have any cracking or broken welds, so this is a good thing.

The rubber could probably use replacing though.

I understand there are a few options on the material that others have opinions on (ill research that on other threads)

 

I do see a factor in my problem though. I see that my limiter bracket appears to be all the way forward up against itself and resting against its 'stopper'.

 

Is the correct adjustment for this as simple as I think… loosening the bolt at the front and putting a pry bar in between the limiter stop and its mount to just jar on it until the spacing is more comfortable and then crank the bolts back down?

Is this a one person job, or am I underestimating the leverage required for this?

 

The other option would be to loosen the bolt, throw it in reverse and back into another guard rail I suppose

(that's a last ditch effort)

 

 

 

Thanks for feedback.

[M3M3M3]

LOL...nah, don't back into a guard rail.

 

loosen the bolts, put jack under the oil pan (with a big board between the jack and oil pan) and just put a little upward pressure on the engine.  enough to make  the limiter easier to move.

 

replace your engine mounts with new stock ones.  for a street car, i recommend not using polyurethane mounts.  the increased NVH with poly is noticeable.

[Kile Brekke]

Thanks for info — I will try that trick to make it easier, but I assume I am right with wedging a bar or chisel between that space on the mount… or is there a better, easier place with better leverage to pry against to move the engine back?