Oil cooler thermostat fixing
Oil cooler thermostat fixing
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Discussion

Lesliehedley

Original Poster:

255 posts

287 months

Tuesday 26th August 2014
quotequote all
Here is a photo of the oil cooler thermostat fixing (I think)on my 400SE. The fixing has crushed the glassfibre and caused a large crack which has been there since I bought it. Does anyone with a 400se have pictures of how this should be attached? Does anyone know what's beneath the glassfibre if anything? Has it just been overtightened and how do I go about fixing the glassfibre? Any help greatly appreciated.


Wedg1e

27,026 posts

292 months

Tuesday 26th August 2014
quotequote all
Looks similar to the arrangement on the 390SE; it's just bolted through the inch-thick lip around the engine bay (where the two shell halves are bonded together) - there's nothing underneath but fresh air (on my car).
Probably a combination of tight nuts and heat over the years - maybe some impact damage from a collision elsewhere on the shell, just not spotted at the time? I seem to recall seeing a 400SE that had front-end damage that had cracks radiating from most corners and edges forward of the windscreen.

MrPicky

1,233 posts

294 months

Tuesday 26th August 2014
quotequote all
The 390SE wasn't fitted with an oil thermostat when it came from the factory in Oct 1985.

Did these become standard at some time after that?

Russ

Wedg1e

27,026 posts

292 months

Tuesday 26th August 2014
quotequote all
MrPicky said:
The 390SE wasn't fitted with an oil thermostat when it came from the factory in Oct 1985.

Did these become standard at some time after that?

Russ
Mine was registered in September '87.

adam quantrill

11,672 posts

269 months

Tuesday 26th August 2014
quotequote all
I have this on mine and made the same mistake when tightening - the glass fibre is easy to crush especially when spannering from below - you can't feel it above the nyloc drag. Mine has been like that for 3-4 years (when I replaced the radiator) and hasn't got any worse so you could just leave it alone.

Lesliehedley

Original Poster:

255 posts

287 months

Tuesday 26th August 2014
quotequote all
It's difficult to see in the photo, but just below the mounting bolts there is a bulge in the fibre glass and the bracket is about a quarter of an inch below the level of the glassfibre either side of it. I'm sure that is what has caused the crack to the left in the photo. How do I go about repairing the crack?

Wedg1e

27,026 posts

292 months

Tuesday 26th August 2014
quotequote all
Well it could be one of those cans of worms once you start, but ideally grind it out with a burr in a Dremel or similar, to a good depth and width, then use polyester resin to fill it (mask any open ends to stop the stuff dribbling). Use the burr to create some nice Vs and gulleys for the resin to flow into, it'll help it to key to the surrounding GRP and prevent it from cracking loose.
You could just fill it with Isopon or similar car body filler, it's not likely to be a structural issue; either way you'll be needing to touch the paint up afterwards.
The recessed surface caused by the thermostat mounting bolts would be a bit more difficult; I'd be tempted to fabricate a spreader plate in alloy or stainless steel and use it to hide the damage.
IIRC you're up here in the frozen north, I've used both E&F Fibreglass Products (Hartlepool) and East Coast Fibreglass (S. Shields)for materials in the past - both extremely helpful.