Specific oil leak questions

[Welcome to Hell A]

Hi, longtime lurker, first time call...err, poster.

I have a few questions. Okay, it will probably end up being more than a few in the end, but I've done as much research as I could before coming here. I'm planning on replacing the front main oil seal, timing cover gasket, valve cover gaskets, power steering hose(s) (if in fact that is where the leak is), oil pan gasket and anything else that needs to be done once it is disassembled.


Where is the oil coming from that is pooling on top of the valley gasket? (guessing valve cover)

Is "The Right Stuff" gasket sealant okay for the timing chain cover?

What kind of thread sealer (name, brand) should be used on the timing chain cover/water pump bolts? Which of these bolts need the thread sealer?

I'm thinking of replacing the timing chain/gears since I'll most likely be in that far once I pin down the source of the oil leak. The Disco has 138k on the odometer. Good idea? I've no idea if it was done previously before I bought it at 92k miles.

Does the new front main oil seal stick out a little once it is fitted? Pretty sure I saw someone say the new ones do.

Does anybody actually use Bostik 1775 sealant for the valve covers as recommended by the Haynes manual and the Rave CD? I can't find that stuff online anywhere, or I'm not entering the correct search strings. How about a recommendation on what to use there? I replaced the valve gaskets about 1.5 years ago and the oil leaks returned too quickly. I screwed something up.

Recommendations for gasket sealer besides "The Right Stuff"?

Any other recommendations would be gladly accepted. (cue PT's plug for camshaft renewal, see I have been lurking a long time lol) In advance, thanks for the suggestions and advice.


Jeff

 

[Welcome to Hell A]

Hrm. I put my vehicle in my signature but it's not showing for some reason. It's a 97 D1.

Will a golf tee fit in the oil cooler lines to plug them? What would work better?

 

[RichardS]

I went through what you are talking about last year on my 96 DI when I had about 115k miles on it, here's my experiences.

Right stuff has held up fine on my oil pan and I assume any automotive RTV silicone would work the same. It would probably be fine on the timing cover as well. I used some Yamabond (similar to Hylomar) on the paper gasket for the timing cover since it is thinner than RTV. I forget which bolts need thread sealer, you should be able to find that in the shop manual. I used right stuff on the threads.

I used nothing on the valve cover gaskets and again, they have been just fine. You have to be careful when placing them if you do not use any sealant as there is nothing to keep them in place, but in my experience the rubber seals just fine without any sealant on it. And I'm assuming here you are using new gaskets as the old ones are likely to be dried/cracked/shrunk from heat and age.

To get the valve covers off easily you are going to have to pull the heater hoses and the plenum. Good time to put new heater hoses on and flush the rad. I replaced all of the cooling system hoses since they did not look so great and I had no idea how old they were. I replaced the expansion tank as a preventative action since I hear they are prone to failure and they are pretty cheap. You will need some sealant for the plenum and Yamabond (or Hylomar) is great for this application.

I replaced the timing chain and gears while I was in there, old one was not too bad but it was inexpensive and easy to do so I did it. Got this from D&D (aluminumv8.com) cheap, it was a take off from a new motor that he was building up with aftermarket parts.

I put the front main seal in flush with the cover. I measured where the lip was on the original seal before removing it and the lip was in the same place when the new seal was installed flush. I suggest you measure as there may be more than one spec seal available. Another suggestion here is to carefully inspect the machined surface on the balancer where the seal rides. Mine was not pristine so I put a speedi-sleeve on to renew the surface. These are made by SKF and can be ordered through bearing suppliers. Another option may be to turn it down on a lathe it but I decided the sleeve was likely to seal better since now the OD of the machined surface is slightly larger vs. slightly smaller if it were turned town.

I decided not to do the cam as I do not have any glaring symptoms of it being bad. To me the extra expense and time was not worth it as a preventative action. I do not put a lot of miles on the truck so that factored in. If yours is a DD and you do a lot of miles you might choose to just take care of the cam now while it is convenient rather than some time in the future when you have to.

While I was doing all of this I pulled the oil and trans cooler lines and had them rebuilt at a hydraulic shop. I decided to buy new PS lines as I found a set for under $100 and that was about the same price as having the old ones rebuilt.

I'm now leak free except for the PS box which has a leaking seal. It's not that bad so I'm ignoring it until it gets bad enough to need replacement.

 

[Welcome to Hell A]

Thanks RichardS.

I am probably gonna use RTV for the oil pan instead of The Right Stuff. That has always worked well in the past. So, nothing for the valve cover gaskets though, huh. That worries me, but I'll go with it.

Is there any other source than leaky valve cover gaskets for pooling oil on the valley gasket? Oil is not flinging up from below, but I can't see where it's seeping from either.

Any opinions on the potential condition of the chain? Is there even a recommended renewal time?

Why did you pull the oil and trans cooler lines? Just because you had it apart, or...?


Thanks again.

 

[RichardS]

I dunno about oil in the valley pan, did not have that on my truck. Mine was leaking a bit from the lower ends of the valve covers, down onto the exhaust. Hopefully one of the guys who works on a lot of LRs will advise on this.

I've never heard of a replacement time on the chain, don't see it in the manual nor do I see a spec on measuring a worn chain, it just says to inspect and replace if worn. Seems good measure to replace it when over 100k and you are pulling the timing cover off to replace the seal.

Trans and oil cooler lines were on my list of preventative things based on reading here and other LR boards. Apparently they have been know to burst once in a while, and that could mean a real bad day if the fluid got on the headers and caught fire. Since they are rubber and were 10 years old I decided to have them rebuilt.

 

[Lutzgaterr]

IF you do have a shop that can rebuild your Tranny and Oil cooler hoses, that is a better approach from a cost and longevity perspective that purchasing new replacements.

 

[Welcome to Hell A]

If oil is leaking from directly around the bolt head that holds on the valve covers, was it tightened too much or too little? I didn't have a torque wrench that went as low as the spec for the valve cover last time, and I want to get it right this time if that was the reason. It seems strange that something like the valve cover gasket repair is so finicky.


Oh. Is it possible that oil from the rear main seal is making it's way up around the front of the engine? I had it sprayed off and the only places I can see the oil leaking from at the moment is the rear main and the valve covers. It just doesn't seem likely to me, but thought I'd ask anyway. Thanks.

 

[ptschram]

valve cover gaskets have nifty little metal rings that prevent you from overtightening them. I use high-tack to hold the valve cover gaskets in place. Leaks from the intake manifold/valley pan gasket can result in oil pooling on top of the valley pan. I've always used the stock paper gasket for the front cover. If you're that concerned about sealing the bolts, I believe the FSM says RTV on them. Right stuff is the only stuff for oil pan gaskets. Make yourself some alignment pins for when it goes back on, you'll thank me later for this suggestion. The oil pan bolts are 5/16-18.

I think that about covers it-oh yeah, a handful of compression fittings/hose barbs and a coupla feet of hydraulic hose and you have new cooler lines for pennies.