Lotus Elan and Lotus Elan Plus 2 Forums

hi there and hope you enjoyed the weekend (lots of motorsport!!!) - the added picture/sketch shows where i have a leak (pressure tested at a bit more than 0,5 bar (1500psi psf?) - nowhere else - so i figure i can at least exclude the head, right?? cheers sandy PS - i hope i'm closer and hope for THE answer

glad you're nearing down the problem - in case it helps :

lotus-twincam-f39/coolant-sump-problem-t29484.html

if it's not the head, then where does it actually leak????? sandy

Hi Sandy

Your drawing shows its leaking from the top of the back plate and down between the top of the back plate into the chain drive space and down to the sump.

It could be a head gasket leak or it could be a leak through the paper gasket behind the back plate. The head and front cover need to come off and the gaskets surfaces checked for flatness and then reassembled. When dismantling you may be able to see the leak path in the gasket

cheers
Rohan

my english pal was saying it must be a leak in the pump's O-Ring area and possibly the 2 surfaces which "encompass" the pump parts. he also says, if theres no other leaks from the top, then it can only be....... as above described sandy

The o- ring seals the pump assembly as it goes through the back plate. The back plate gasket seals the back plate to the face of the block and seals where the pump impeller goes into the block. An o-ring leak is more likely to leak directly into the cover chain chamber around where the front cover and back plate join rather than at the top of the back plate.

Has the back plate paper gasket been fitted ?

cheers
Rohan

yes and done very carefully with 3bond rtv! sandy BUT: i messed up a bit, because the stupid cork gasket was almost disintegrating; so at the backplate top i may have missed/"lost" 1-2sq.mms????? as the engine was only running for 10min +/- i couldn't see any channnels! sandy

HI Sandy
If its not the back plate gasket leaking then it must be the head gasket leaking. The cork gasket at the top of the front cover is only to stop oil leaking between the head and front cover it does not seal against water leaks from the cooling system.

cheers
Rohan