I have a '67 420 I purchased last June. Been doing a bunch of servicing, rebuilt brake system, rear suspension, new cooling hoses and water pump. Carbs and fuel system redone as well.
When I got to doing some test drives, I noticed streaks down the sides of the block. More on the right side. I checked and it didn’t appear to be antifreeze, but didn’t feel like oil. It seemed to lessen the more I drove it.
Rolling a few months ahead. I’m doing a conversion to 4 speed overdrive transmission I hope to have soon. When looking up under the engine I see the streaking was from the head and residual antifreeze drops are present. I put my cooling system tester on at 7 psi and it is holding hours later. I think there’s the slightest weeping going on. Part of me says just leave it. A bigger part of me says pull the engine since its nearly out and replace head gasket and also do a reseal, leaving internals alone. Also thinking of new lower timing tensioner. Or should I do the timing kit? I’ve heard of bad timing parts out there. My engine has great oil pressure and compression is good too. Its only got 28000 miles on it, but it over 50 years old…
Pull the engine. Since it runs and is hardly worn in: New gaskets (de-coke set), but leave the lower chain and bottom end as is, if you ask me. It’s not that much of a job unless the valve clearances are off or there is something wrong.
Can valve springs go bad from sitting?
You‘ll be happy when everything is clean and the gaskets are new.
If it ain’t broken, only fix what weeps. Isn’t the transmission easier with the engine out anyways?
Have seen this before on my S-type.
They used water in the cooling system for many years.
After I pulled the head all water cooling holes in the head were eaten away.
I needed another head.
I did retorurqe it. After having 7 psi all day, I had a few drips forming on the LH rear of the engine also a weep build up on right side. My engine had antifreeze in it and looked very clean inside block water ways when I had the water pump and thermostat removed. I hope its just the head gasket getting old. Worst case I do have a spare head I’ve been getting ready to build up.
Ok, engine out and head off! Actually not too bad. The head was starting to get surface corrosion which is probably why I was getting weeping. I’m probably going to try cleaning it up and see what I have. I may strip the head and have a skim cut done. Probably touch the valves up. I hoped I didn’t have to do that so the valve clearances don’t get changed. I guess its not the end of the world. I’ll reseal the rest of the engine less rear main, since it was fine!
I would clean the head and see if it’s straight and maybe you don‘t have to remove anything.
Same for the valves, pour in gasoline and see if they weep. Maybe you are lucky.
Purists and perfectionist will be horrified but back in my decades as a Jaguar warranty administrator we had a corrosion, or aluminum erosion, issue with some of the heads on circa 1992-94 AJ6 engines. The manufacturer approved repair was to clean the mating surface well and apply J B Weld, sand it down even and replace the head. Seemed to work fine.
