Lotus Elan and Lotus Elan Plus 2 Forums

jk952 wrote:If memory serves me correctly, the small bolt & hole just above the generator/alternator that goes “up” into the head from the lower chain case is open to the head chain area so can seep oil down the threads; suggest removing and adding thread tape or suitable goop (rtv). I just did on mine and think I have stopped my leak, but winter so will find out for sure later...
Jack

Good tip! I've got an annoying leak in the area, and might be my problem. Thanks!

...................when i see BAY AREA, i get confused as there's must still be a big difference between tiburon and oakland?? sandy (i once lived in mill valley)

+1 to RichardCox and JonB point to cam-cover - The cam covers have a habit of turning up at the front. I just had 2 cam covers machined flat ( a spare and one off the car) - oil was seeping out of an engine that did not leak oil for years.

take a thin feeler gauge and probe the gasket seal - if it slides in then oil can come out ..

webbslinger wrote:When I asked if you had an oil cooler in my previous post, I was thinking about your new fan and your mention of oil on the lower part of the radiator and crossmember. With all the leaks I've had (every one described here so far) I've never seen oil come forward like you describe, or seen drops flying around. It got me thinking about an oil cooler leak. I'm curious, please let us know what it turns out to be.

No oil cooler.

cabc26b wrote:+1 to RichardCox and JonB point to cam-cover - The cam covers have a habit of turning up at the front. I just had 2 cam covers machined flat ( a spare and one off the car) - oil was seeping out of an engine that did not leak oil for years.

take a thin feeler gauge and probe the gasket seal - if it slides in then oil can come out ..

Ah now, I was talking about the timing chest seal on my car, which is new and leaks. Cam cover too, but I RTV'ed both sides of the gasket (previously only the cylinder head mating surface had the stuff) and it's not leaking there any more. For the timing chest seal I nipped up the bolts either side which improved - but hasn't cured - the leaks.

Personally i don't think silicone gasket formers / sealants such as RTV is the best as a gasket sealant and I only use it very sparingly in very specific circumstances. This style material is useful for forming a gasket when applied by a computer for original assembly of accurate metal components using the correct grade on a production line for modern designs intended for it but in the hands of most people rebuilding a twink it tends to be over used or squeezed out of the join and subject to all sorts of problems as a result. Not saying it cant be made to work but you need to be very careful in using it and understand its properties versus the join or gasket your using it on.

In my experience on twinks I believe the correct grade of anaerobic gasket former's are better for the metal to metal joins and various gasket sealants ( hylomar, loctite aviation gasket sealant etc ) better on the cork and paper gasket joins..

cheers
Rohan

Rohan, I used a clear RTV sealant on the timing chest and other seals. Specifically this stuff: https://www.granvilleoil.com/techData/p ... ?ptdID=133

Which I see now is for doing windscreen bonding? Have I erred?

I would not have used it and have seen poor results on engines built using similar products. That type of material does not have the required bond strength for sealing gaskets to metal faces as its viscosity is low and it tends to squeeze out. Similarly in a metal to metal join it squeezes out and and fails to form an adequate gasket.

There are specific products for both these situations rather than RTV water proofing style products

cheers
Rohan

Could you offer some suggestions? “Aero grade sealant” as mentioned by several members doesn’t mean much to me. I’d love actual product recommendations if possible.

JonB wrote:Could you offer some suggestions? “Aero grade sealant” as mentioned by several members doesn’t mean much to me. I’d love actual product recommendations if possible.

For some recommended sealants you may wish to refer to my old post on Burton Water Pump fitment issues:

viewtopic.php?f=39&t=43910&start=15

The only further things I would like to mention based on more experience is that for the head to timing case cork gasket use Loctite MR5009 Hi Tack on the bottom face only and use Loctite 534 Hi Tack stick on the top face. This is because the MR5009 has a very tenacious grip and if you use it on the top face the cork gasket is liable to tear whilst you position the head. The 534 on the other hand has a consistency like grease and unlike the 5009 cures anaerobically so you have time to position the head. I wondered why the original Lotus manual specified a different sealant for the top and bottom sides of this gasket and found out the hard way why!! The Hi Tack is exactly that as it really sticks and so helps stop the cork from extruding.

I also recommend using the QED gasket which is an aluminium reinforcement sandwiched between a cork layer each side. This is as per the original specification Ford used for sump gaskets and suchlike and seems to resist extrusion and last longer than the more typical one piece cork/rubber granule mix gaskets you buy these days and that don't have a metal reinforcement.

Thanks for that, I'll look into it.

Just to be clear, I used Granville clear "Instant Gasket" sealant. "Replaces preformed gaskets. Non shrinking. Remains flexible. Resistant to high temperatures, transmission fluids, water & antifreeze."

This stuff: https://www.halfords.com/workshop-tools ... gasket-40g

JonB wrote:Just to be clear, I used Granville clear "Instant Gasket" sealant. "Replaces preformed gaskets. Non shrinking. Remains flexible. Resistant to high temperatures, transmission fluids, water & antifreeze."

I have no experience of that particular brand although personally I always try to use the major brands:
1. Loctite
2. Permatex
3. Threebond

Loctite and Threebond are what OEMs use. Threebond is used almost exclusively by Japanese OEMs

Beware that not all silicones are the same. Some are more engine oil tolerant than others, some are more ATF tolerant than others, some are more glycol tolerant than others, some are more heat tolerant than others, etc.
On good flat machined surfaces using a gasket often no sealant is best.

If you can't get some of these sealants in your local area Ebay may be your best friend. Sometimes Loctite especially (eg. with Hi Tack) has the same or very similar product labelled differently for different countries just to make things confusing!

Not coming from the cam cover joint.

The plan right now is to get everything as clean as I can, run it again and see if the source becomes obvious.

Update: I got in there and wiped up all the oil I could. Nothing seemed super-obvious as the source but after pulling the alternator and cleaning the area that it obscures, the dipstick tube is more suspicious than it was before, as there was more dirt stuck in oil around it than anyplace else. I also checked many bolts for tightness. The sump bolts were all barely more than hand-tight, so I gave all the ones I could get to a little snugging, nothing crazy. Had a problem with another bolt but I'll start a new thread about that since it's not the leak but is a different issue altogether.

jk952 wrote:If memory serves me correctly, the small bolt & hole just above the generator/alternator that goes “up” into the head from the lower chain case is open to the head chain area so can seep oil down the threads; suggest removing and adding thread tape or suitable goop (rtv)

More bad news. I just checked this bolt and thought it seemed loose. With very little torque applied -not even beginning to feel tight- the thread in the head stripped!

I can't begin to express how angry I feel about that, but at least I didn't scream much of a curse lest Mrs. Veg come running to the garage in horror that I'd injured myself.
At least I don't think the bolt was much of a leak; there was hardly any oil on it.

I guess now I have a good stiff drink and get ready to pull the head.