Apologies - I realise this topic has been written about before. I’m fighting a coolant in oil problem. I have a '68 E-type with 6-cylinder engine. It was not running when I purchased the car, so its previous history is unknown. I’ve had the head decked and pressure tested to 500kPa. It all came up well and there appeared to be little signs of any corrosion in visible areas at least.
The head has been off a few times now. I’ve paid a lot of attention to surface cleanliness, torquing appropriately, etc. I still end up with coolant in the oil. There isn’t any steam out of the exhaust or coolant in the cylinders. This would suggest the cylinder head is ok and the problem is possibly associated with the timing cover. I’ve inspected the gasket around the water pump and it doesn’t appear that water has made its way via the cam sprocket shaft into the oil. The timing cover is really in very good condition with very minimal pitting. There is the rectangular water gallery in the block connecting to chamber behind the pump in the timing cover. That seems like the only potential area for coolant leaks. The coolant and oil become emulsified into a milky substance pretty quickly. There’s no separation of coolant and oil as I’ve had in some other cars. The engine does run well - besides this issue. Compression and oil pressure is good and it purrs along happily.
Although I’ve had the head off a few times, I’ve only removed/replaced the timing cover once. I didn’t use a paper gasket, just the blue silicone. Maybe this is the problem?
Any other ideas? Any preferences on gasket use, silicone use? Is Aviation sealant a better option with paper gaskets?
Done properly, a thin schmear of silicone on the front cover sealing surfaceis perfectly acceptable: you could have a cracked block, on a lower surface of the cooling jacket.
You may want to take a close look at the minor pitting on the timing cover. I found the same pitting behind the water pump, when I cleaned the corrosion product from the pits, found that one pit extended through the cover. Was a pinhole at the bottom of the pit.
You may have nailed the problem Ed as I’ve changed several timing covers on engines that I was working on because of severe corrosion engines in that area. I would bet that someone that works on these engines on a regular basis has seen this problem more then a few times.
Bob
889076
Plymouth, Mi
I agree with ED, I had to fix this very issue in the timing cover, of a 64 E and had to get the pin hole in the bottom of the water pump recess welded twice without warping the cover.
With the timing cover and water pump installed, remove sump and pour water into the water jacket and or the water pump hose and see if it comes out the crankcase.
The head came off quite easily, without removing the headstuds, which were all very clean. I wasn’t planning on removing the headstuds unless it was absolutely necessary. I’m not saying it’s not possible - maybe?! But if the coolant had made a path up the thread studs, ,then I presume this would have happened at a fairly slow rate. In my last run, the coolant got into the oil fairly quickly - there was even globules of coolant floating around under the cam covers. I’ve just been cutting some new paper gaskets for the timing cover and polishing the timing cover gasket surfaces in case there were any irregularities or high points there. So far so good.
I’ve always used The Right Stuff which is very effective, but messy and will make it hard to separate, say, the cam cover from the head. Then Dick Maury recommended I try Permatex Ultra Black Gasket Maker. The stuff is fantastic. Thanks Dick.
For those interested, I pressure-tested the coolant system and found coolant making its way into cylinder #4 and the sump. Probably the worst outcome. As I’m happy the head and headgaskets are good, then it looks like a liner. So out with the engine I guess and a full refurbishment of the block.
Hi Freoway3, I went down this road a few years back on a rebuilt engine, head rebuilt and decked etc. I started to notice what you are seeing and it drove me crazy as the block, cylinder liners and now the head with a new gasket should have solved the problem.
I was so disgusted that I parked the car for a couple of months and we were not on speaking terms.
Then with a cooler head (mine) I started to do the forensic work on what I had missed. It came down to the cylinder head bolts themselves. I noticed that the bolts between cyl. 4 and 5 were standing slightly taller. This was not due to a mixup of the longer bolts which facilitate the lifting lugs on the head.
I pulled the bolts and found that the holes down in the block had 3/16" of compacted crud at the bottom. I modified a long drill bit to mine into the crud and break it up, then removed and vacuumed the entire block, all bolt holes down to bare metal.
The problem being that the dome nuts could not exert the needed torque value to seal the head properly with the offending bolt holes. Had I been using a common open nut, it would not have been a problem, but the dome nuts were bottoming out and left this section of the head sealing area under torqued. All assembled, with new head gasket and factory approved sealants, the problem disappeared.
Before you pull your engine try this route first, couple of pics attached. best regards, Brian / mytype
Hi Brian, Glad to see I’m not the only one with a belligerent Jag that should probably also get the cold shoulder for a couple of months. Thanks for the useful forensics and associated pics. It’s definitely an avenue to explore. o ask Possibly a rhetorical question, but how does that much crud get down the bolt holes?! A previous owner’s sloppy work? I actually haven’t removed the bolts, well not yet anyway. I was lucky that the head slid nicely over the headbolts, which may mean that someone previously had already cleaned them up. I’ll take the domed nuts off tomorrow and run a straight edge over them… and report back. I’ll probably remove the head anyway. There’s a good chance I’m removing the motor, presumably from underneath, so it’ll be a lot easier without the head. I find it easier to take the head off than the inlet manifold anyway. That’s a nice looking engine bay.
As you remove dome nuts, it could be worth careful consideration of washer thickness, bolt length above head, and internal depth inside each dome nut. There are various internal clearances on dome nuts, many are the same but there some out there with shorter internal clearance.
And you could try open nuts at suspect locations. This could allow testing again for leak without much teardown and also would permit bolt stretch measuring to verify torque.
Lloyd, my block is a donor from an xj6 as the original was time X’d and had already been bored out 40 thou. The holes and the bearings on the donor (short) block where all standard, so I was starting fresh and I elected to do this instead.
However, to answer your question re- the block-crud, somewhere back in time I suspect that the head had been off and that the work done had precluded a complete draining of all coolant. This would have prevented a detailed inspection and de-crudding of the bolt holes themselves,… but then why bother, what could possibly go wrong?
I got an education and any future block work now entails the above, along with the use of a piece of 2 x 4 drilled to take the head bolts as they are removed. This keeps them in sequence. It is imperative that the bolt holes are cleaned and bottomed out properly (with never seize on the threads) or the dome nuts will not be able to do their job. Couple of pics on engine removal if necessary… I prefer the out the bottom method. best regards, Brian / Mytype.
