1953 100-4 oil in the radiator fluid

[norway330]

Hi all,
I just had my 100-4 engine rebuilt and after about 1000 miles of driving it, after the rebuild, the car runs great. The exhaust gases look clear when the engine is hot. The oil which was just changed looked dark but clean. No foam.

What I have noticed, however, is that the engine coolant was down about a gallon. So coolant is leaking somewhere. It's not evident on the garage floor. When I filled it to top again I noticed a thin film of oil floating on the top of the radiator filler hole.

This is not good. Please give me all of the possible situations that could be leading to this problem. One can hope that pulling and rebuilding the engine again is not one of them. Again there does not appear to be coolant in the oil.

Thanks

Bob

 

[Keoke]

BOB

It may not require a complete engine rebuild .However it may involve a crack somewhere in the head or the engine block.

 

[Brinkerhoff]

Bob , go buy an oil analysis kit from a diesel truck repair center and send a sample in. It will tell for sure if there is coolant in the oil which would be bad of course and would need to be fixed. If there isn't, I wouldn't worry about a little oil in the coolant. Kevin

 

[norway330]

Thank you ...will do

 

[red57]

Don't know if it happens with the 4 cylinder motors or not, but the 6 cylinder (100-6 & 3000)blocks can develope a problem with 'block porosity'. Some oil gallerys are close enough to water jackets that after some years of rusting internally in the water jackets the wall between them and the oil passages gets a bit thinner and natural pourosity of the cast iron allows oil to seep through under pressure into the water jackets (oil at 40psi, water at 7psi = oil wins). Several suppliers sell oilway repait kits for the six, I just don't know if it's a problem with the 4 banger or not.

A few years ago I ran a six with this problem for several years - periodically I would flush the motor by adding detergent (laundry soap) and run until fully warmed and then drain and repeat until it ran clean water through and then I was good for another 500-1000 miles. If I let too much oil get in the water it would form a sludgy mix that didn't flow real good and temps would rise.

One positive is you don't have to worry about adding water pump lube.

Dave

 

[dougsmarkIII]

A few years ago I ran a six with this problem for several years - periodically I would flush the motor by adding detergent (laundry soap) and run until fully warmed and then drain and repeat until it ran clean water through and then I was good for another 500-1000 miles. If I let too much oil get in the water it would form a sludgy mix that didn't flow real good and temps would rise.

One positive is you don't have to worry about adding water pump lube.

Dave

I believe you meant to say I would flush the radiator by adding detergent.

Doug

 

[Michael Oritt]

Bob--

100's are notorious for cracking heads and blowing head gaskets, esp between 2 and 3. Sometimes gasket leaks are not so bad as to be noticeable from the outside and the coolant can go out the tailpipe as steam--and oil can in turn seep into the coolant after shutdown, etc. This would be a fortunate scenario and I would pull off the cylinder head to check the condition of the gasket--maybe you'll get lucky.

 

[Genos2]

Are you building excessive pressure in the cooling system? What I usually do is attach a pressure tester to radiator-warm up engine & see what amount of pressure builds on the gauge on the tester.Not sure about our 100's, but normally 7 to 9 lbs. would be allowable. If in spec, I also use a head gasket checker that involves a blue liquid that that yellow when carbon monoxide(combustion) is present in the cooling system. 100's are prone to cracks in the combustion chamber to the water jacket, into oil galleys isn't typical. If test are positive, I would remove cylinder head & have pressure checked, Good luck, Genos2

 

[Keoke]

A few years ago I ran a six with this problem for several years - periodically I would flush the motor by adding detergent (laundry soap) and run until fully warmed and then drain and repeat until it ran clean water through and then I was good for another 500-1000 miles. If I let too much oil get in the water it would form a sludgy mix that didn't flow real good and temps would rise.

One positive is you don't have to worry about adding water pump lube.

Dave

I believe you meant to say I would flush the radiator by adding detergent.

Doug

Naa He is OK can't do one without doing the other using his technique.---Keoke-- :thumbsup:

 

[Randy Forbes]

The two (2) main things to take away from these suggestions are:

1. the oil analysis. Blackstone Labs will send you out free sample kits and then return it to them with $25-$30 for the test results a few days later. I use them dozens of times a year (been doing oil analysis on ALL my cars for over 30 years now). https://www.blackstone-labs.com/free-test-kits.php

2. the chemical combustion test; this kit should be available from your local NAPA, or they can order it for you. As stated, the mixrure is added to the coolant, and if there are particles of combustion present, there's a reaction.

No point in pulling the cylinder head, unless you know that there's no way to avoid it. Good luck!

 

[Healey 100]

I suggest you do nothing. Just relax and enjoy your Healey for the next 1000 miles. Check the water level regularly and keep an eye on it.

When an engine is rebuilt there is plenty of opportunity to drip oil into the water jackets. This stray oil will show up eventually at the top of the coolant in the radiator. A good flush would get rid of it.

I would be more concerned about the loss of coolant, but even that has simple explanations: was the system filled properly to begin with? The weather has been hot, did the car just boil off some coolant after a hot run? Overheating is common for a freshly rebuilt engine when the friction is high. Operating it for few thousand miles usually resolves this problem.

I think chances are good your engine is just suffering from rebuilding housekeeping or normal British leaks. Note the 100 is famous for leaking water out of the head gasket above the distributor. Mine has done this for years through a couple of rebuilds -- but it seems to do little harm.

Hope this helps,
Bill S

 

[roscoe]

Some folks scoff at additives like Irontite, but I treated my cooling system with it just after I rebuilt the engine and I have not had a drop of coolant disappear, a spec of oil in the coolant or any head gasket seeps in 4000 miles. My engine runs at decent temperatures. I did not retorque the head bolts post run-in. You might look into it if the problem persists. It was one of the things Norman Nock suggested to me (British Car Specialists).

 

[tahoe healey]

Any chance you need to re torque the head. I've heard that is a problem after a rebuild on the 4 cylinders after the first 500 miles. The center ones tend to cause leaks and problems. Just a suggestion as I have a 6 cylinder and don't have that problem (and of course I don't know what I'm talking about). Oh, I see roscoe suggested the same thing.

 

[roscoe]

Actually it was recommended that I NOT retorque the head as it may actually cause leaks, rather than prevent them. It sounded strange to me, but I refrained.

 

[Randy Forbes]

Actually it was recommended that I NOT retorque the head as it may actually cause leaks, rather than prevent them. It sounded strange to me, but I refrained.

This is my belief as well.

If you're going to retorque a cylinder head, you need to do it after the first time the engine starts, gets up to operating temperature and cools down.

I would not do it after 100 or 500 miles (unless that was the first time the rebuilt engine was fired up, and driven to reached operating temperature, etc.).

 

[BoyRacer]

As for re-torquing the head on the 6 cylinder engines: You do it because we have head gaskets that are composite and around .050" thick. They compress around .010" or more. If you have an iron head you do it while the engine is still hot. If you have an alloy head you do it after the engine cools down. If your engine is completely stock you may get away without re-torquing the head. But, why take a chance. You do not have to re-torque immediately - just do it before the head gasket is compromised.