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36' Buick series 40 - 233 engine oil/coolant issue


Manu

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Hi. My name is Manuel. I am from Luxembourg Europe. I cannot find help here in Luxembourg. That's the reason I joined this forum. Since 2 weeks, I own a 36' Buick series 40, all original with 233 engine. I bought the car in Belgium. A few days ago, I checked the coolant level. There was coolant missing. After this I checked the oilstick and I was shocked about what I saw. What can be the reason for such an oil color. Coolant in oil? Since I bought the car, the car was not driven. The last owner had shown me the oil dipstick before I picked the car up with a trailer and everything looked normal. I am frustrated. It is very hard to find someone in Luxembourg or around my country who can repair the engine. I made a video during the oil change. The  oil looks exactly the same. I cannot attach the video, it's too large. Sorry for my english, I do my best 🙂

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Manuel,you certainly have a problem.I am not familiar with that engine. You may have a blown gasket or a crack somewhere.I would scroll down to the Buick forums and ask questions there.Some one with knowledge of your particular engine may be able to tell you where the problem could be.

 

Your English is just fine.I have trouble with it myself and I have been speaking it for 71 years!

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FYI if you want to share a video with this message board, you should post it on YouTube and then you can put the URL link in your posting.  
 

Yes, that looks like “water in the oil”.  First thing people think of when they see this is blown head gasket.  
There can also be a crack that allows the cooling water to get into the crankcase.  
Either way, the cylinder head is removed (typically you can see where it leaks) then you carefully examine the head for cracks.  
The Buick experts will pipe in and tell the most common places to crack and leak. 

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That's a green 3 window sports coupe, right? The seller in Belgium bought it from Ireland and was just flipping it. I guess he knew only little about the car. I had sent the former owner a message some time ago, because I was interested but never got a reply. Cannot find it anymore. I am sorry. He would probably be able to tell you more. But the car then was not advertised with an engine problem.

The straight eight engines are not rare or costly. Worst case you need to import one from the US. That's of course no fun, but manageable. The car I recall is a great looking car. Congratulations! Don't let you drag down by this, old cars always give trouble. That's part of it. Hans from Cologne 

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We need some of the Buick straight eight people from the Buick Prewar forum in this thread. Something about this engine does not look right to me but I am no expert. Being a 1936 40 series, this should be the LAST year of the earlier small straight eight engine design, right? Could the engine we are looking at in the pictures be later?

 

If it were a larger series Buick in 1936, it would be the FIRST year of the 320. Those first year (1936) 320s ran coolant through the rocker shaft, and no, I'm not kidding. Coolant leakage into the oil is a definite possibility. Does anyone in here know if Buick ever tried that on the smaller (40 series) straight eight engines?

 

 

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Thanks for your replies. Yes Hans, it's the green one. I tried to find an engine in US but no chance 😞 A rebuild in the Nedelands will cost 17000-23000 euros (it's the same in dollars) I have no possibility to spend so much money for a rebuild. I am new in the Prewar scene. Since 14 years, I am in the Mopar scene. I also drive a 69' Dodge Charger. By checking the Buick engine casting number it seems to be the original 233 ci engine.

Buick 36.jpeg

Moto 233 ci.jpg

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Wow, thats a lot of money for a rebuild. Did you try Yankee Motors Gmbh in Nürnberg, Germany? They are specialized in US engines. They have even a price list on their website. I just see they moved, but they pick up engines for a fee in all of Germany. If the block is cracked I have no idea if they can help. I replaced cylinder head gaskets a few times. Not a big deal on straight eights, if this is the problem. Good luck. Still a great looking car. The '36 grill is just amazing. I further looked for the previous owner but couldn't find it. 

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Engine has been running with the water in the oil, otherwise it wouldn`t be in the filter. Looks to be an original 233 with the oil filter added. I`m thinking cracked head or bad head gasket. First, i`d pull the spark plugs and look at them.

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5 hours ago, Bloo said:

Those first year (1936) 320s ran coolant through the rocker shaft

     How and why was that done?  I believe that the oil line on the right front of the head supplies oil to the rocker shaft.  How are the rockers lubricated if the shaft has coolant passing through it?

     I doubt there's an oil cooler but that would be the simplest solution.  

     The cooling system has low or no pressure so a leak between pressurized oil and a coolant passage would most likely contaminate the coolant with oil.

     The oil returns to the bottom through the push rod passages.  The head gasket could be leaking between a coolant passage and a push rod passage.  

     Suggestion:  Drain the oil and leave the plug out.  Remove the valve cover.  Fill the cooling system and apply some slight pressure to the radiator.  Does the water come out the oil drain plug?  Can you see it in the push rod passages?  How freely does it flow?

      Careful examination of the head, block and gasket should reveal a leak if there is one.  

     I hope nothing is cracked.

 

     Comment et pourquoi cela a-t-il été fait ? Je crois que la conduite d'huile à l'avant droit de la tête fournit de l'huile à l'arbre de culbuteur. Comment les culbuteurs sont-ils lubrifiés si l'arbre est traversé par du liquide de refroidissement ? Je doute qu'il y ait un refroidisseur d'huile, mais ce serait la solution la plus simple. Le système de refroidissement a une pression faible ou nulle, de sorte qu'une fuite entre l'huile sous pression et un passage de liquide de refroidissement contaminerait très probablement le liquide de refroidissement avec de l'huile. L'huile retourne au fond par les passages de la tige de poussée. Le joint de culasse pourrait fuir entre un passage de liquide de refroidissement et un passage de tige de poussée. Suggestion : Vidanger l'huile et laisser le bouchon ouvert. Retirez le couvercle de soupape. Remplissez le système de refroidissement et appliquez une légère pression sur le radiateur. L'eau sort-elle du bouchon de vidange d'huile ? Pouvez-vous le voir dans les passages de tige de poussée? Comment coule-t-il librement? Un examen attentif de la tête, du bloc et du joint devrait révéler une fuite s'il y en a une. J'espère que rien n'est fissuré.

 

 

 

 

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3 hours ago, pont35cpe said:

Engine has been running with the water in the oil, otherwise it wouldn`t be in the filter. Looks to be an original 233 with the oil filter added. I`m thinking cracked head or bad head gasket. First, i`d pull the spark plugs and look at them.

Hi. The spark plugs are ok. They are just wet oiled. I think that's a valve stem issue.

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The Lotus 23 has coolant running through the frame tubing from the front radiator to the engine behind the driver.  I guess Colin Chapman wanted to reduce weight by eliminating a couple of hoses. 

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I am not familiar with the '36 engines, but is the temperature gage connection near the rear of the spark plug cover, similar to the '38's?

 

I had a similar oil in water issue with a '38 engine rebuilt by someone else.

On the rocker arm stanchions, the rear, passenger side should have a stud rather than a bolt. That hole is tapped through to the water jacket. If a bolt is used intead of a sealed stud, water will get into the oil. It happened to me and finding it drove me crazy.

Since your engine was recently rebuilt, this is a possibility and very easy to check.

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3 hours ago, nat said:

How and why was that done?

I don't know. Kind of horrifying isn't it?

 

3 hours ago, nat said:

I believe that the oil line on the right front of the head supplies oil to the rocker shaft. 

On 1937 and later 320 that is true. We had a long thread about it when @EmTee's engine was leaking at that spot. There is/was a screen under there. I am not sure if we determined whether the brass fitting was a "jet" or not. On a 1936, I believe a water line connects at that spot. The oil line you are thinking of definitely runs to the back of the head instead on a 1936 320. I am returning from the Buick nationals in Spokane, and probably have pictures of that detail. I have not looked at them yet. Ping me in a couple of days if you are interested.

 

Unless it turns out Buick did this to the small engine too, it wont matter for Manu.

 

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The "Oil Temperature Regulator" which was a line which ran coolant through the rocker arms was only used on the 320 large series engines in 1936. It was not used on the small series engine in 1936, so that is not the problem here. The most likely cause would be a blown head gasket or a leak at the rear rocker arm stanchion stud as Don Micheletti mentioned.  

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40 minutes ago, MCHinson said:

The "Oil Temperature Regulator" which was a line which ran coolant through the rocker arms was only used on the 320 large series engines in 1936. It was not used on the small series engine in 1936, so that is not the problem here. The most likely cause would be a blown head gasket or a leak at the rear rocker arm stanchion stud as Don Micheletti mentioned.  

Hi MCHinson. I'm having a little trouble understanding everything here. I can't find anything specific on the net about how the "rear rocker arm stanchion stud" should look, respective what it should be exactly. Are there any pictures that could be posted here. I am using an online translator to make everything understandable for me. Sorry for the inconvenience 😞

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2 hours ago, Manu said:

Hi. The spark plugs are ok. They are just wet oiled. I think that's a valve stem issue.

Are they wet where you put the socket to remove the plug, or wet where the plug fires/sparks. If puddling where you put the socket, the oil is weeping from the lower rocker arm tower bolts, these need the threads sealed. Temp. sender and stud are located as Don stated, rocker tower over #8, lower has the stud/nut..

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3 minutes ago, pont35cpe said:

Are they wet where you put the socket to remove the plug, or wet where the plug fires/sparks. If puddling where you put the socket, the oil is weeping from the lower rocker arm tower bolts, these need the threads sealed. Temp. sender and stud are located as Don stated, rocker tower over #8, lower has the stud/nut..

Hi. Yes wet where I put the socket to remove the plug. OK thanks, I will remove the valve cover first and check what is going on little by little.

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Once the cover is off this is how that last stud should look without the nut.

You can just barely see the temperature sender below the stud.

It is important that the threads into the head be sealed

 

There are no core plugs inside the side cover

DSCN9946.JPG

Edited by DonMicheletti (see edit history)
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It just happens that I have a picture of that very stud on the 320 CID engine in my 1938 Century:

 

image.png.7285f3c3e208ea64a92d846fd7b12572.png

 

Note that as Don Micheletti said, the mechanical temperature sending unit screws into the water jacket directly below the stud.  If it were me, I would check this first.  Sealing that stud would be a pretty easy fix.  ;)

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It's hard to tell from the photos, but do you see any evidence of coolant leaking around that stud?  Is the area right around the base of that rocker stanchion noticeably cleaner than the others?  Definitely moisture inside the engine, judging from the underside of that rocker cover.

 

When I was troubleshooting an overheating problem with my '38 Century I rigged a way to pressurize the engine water jacket with compressed air to determine whether I had a blown gasket or other leak aside from the radiator.  After chasing-down a couple of leaks in my test setup, I verified that the system maintained 7 psi for an hour without leakage.  (At that point, I was pretty confident that my radiator was the only issue.). You could try something like this on your engine to narrow the source of the problem.

 

image.png.41ff8b0dd62a8002fdae66d8451618ff.png

 

image.png.2f2df12378ba2068c160825b571a0224.png

 

image.png.20449399c166ca920d71d5c0982c61e4.png

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Compression test was done 2 days ago with sobering results.

Cylinders

8 - 4.75 bar = 68.89293 PSI

7 - 4.85 bar = 70.3433 PSI

6 - 3.85 bar = 55.83953 PSI

5 - 5.10 bar = 73.9692 PSI

4 - 6.15 bar = 89.19821 PSI

3 - 4.55 bar = 65.99217 PSI

2 - 5.45 bar = 79.04557 PSI

1 - 3.95 bar = 57.28991 PSI

 

I would like to do a cylinder pressure test. It seems to me that the valves are not all closing properly, which could explain the result of the compression measurement. But this has nothing to do with the coolant in the oil.

 

No I don't know anything of any overheating occurances?

Edited by Manu (see edit history)
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A leakdown test would be helpful, but as you suspect, it may be that leaky valves will dominate the result.  A pressure test of the cooling system would be more helpful in this case.  If you attempt this with the radiator in the system you'll need to plug the overflow tube.  Disconnecting the radiator as I did (ref. above) might make more sense.  If you do this, I would limit pressure to 5~10 psi.

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2 hours ago, Robert Engle said:

Bite the bullet and pull the cylinder head.  New gasket and lap valves will only improve running and you may find your problem

        No doubt that will be required to restore the compression but it's worth looking for the source of the coolant leak while it's still assembled.  Looking for water with the engine full and pressurised or with the engine drained and pressurised the leak may be audible or found by looking bubbles in a soapy spray.

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  • 2 weeks later...

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