The Stovebolt Site Forums The Shop Area Engine Shop My 49 still getting hot

I have not seen any air bubbles in the coolant. not sure what mark noticed as i was not there.

no oil in the water or water out of the tail pipes I guess...

sounds like ever thing that can be covered has... my 52 with 235 never rain hot,, no shroud,..

I would take it to a mechanic

compression test good. cylinder leakage test good. no bubbles in coolant during cylinder leakage test...

A 25deg drop would take 205 to 180, so the radiator doesn't appear to be the problem.

This again says the radiator is not the problem. The water is being heated too much for the cooling system to maintain the correct temp.

I still think the head is the source of the problem. Heat comes from the engine. If the water flow through the block and the heads is unrestricted but temp is still too high, the head gasket is the only thing I can think of that could cause the problem.

Exhaust gases are @ 500deg, so it wouldn't take much exposure to superheat the water to the point that the cooling system cannot cope.

That's certainly a possibility. If the gasket isn't a 235 gasket, and water ports are blocked, that would account for the excessive heat.

In either case, I think the culprit is the head gasket or head.

just spoke with mark and i am going to pull the head. will post with results. thanks for all of the help.
Joe.

OK: This might be helpful, or not. I had a 57 Jeep. I know not a bolt, but an interesting issue any way. Would idle for ever with out over heating. Would drive in town no overheating. But when you went over 45 MPH HOT!. Worked all the stuff that has been discussed here any way. Took the head off 2 times. Looked at every thing and still over heated when I went faster than in town. The real problem? Head was warped. Not much but just enough that exhaust gas was leaking into the water jacket. Only a little. So when the pressure went up, drove a little faster it super heated the cooling system. When I went just a bit faster it over pressured the coolant and pushed it out. Since I was on the road I could never tell why. Head gasket was not damaged, go figure. I would pull the head and check if it is true and flat and if it is cracked. Had the head milled and the problem went away. You might have something like this. Not a big leak, just enough to cause a lot of head scratching. Good luck and let us know what you find.

Have you tried running the fan full time? In a normal acting cooling system the electric fan/radiator are sized so that they can remove more heat and faster than the engine can produce it. Therefore, ram air can keep the coolant temperature under control most of the time.

In this case, the radiator is sized for an engine fan turning all the time (and close to the radiator) so by letting the coolant get to 185 before the fan comes on, the block and head have heat soak that is above the curve before you start the fan.
The fan on all time can't overcool because the thermostat will take over.

What sort of thing will blow a head gasket? I'm wondering if I did something to cause it...

Edit....Never mind the question..I googled it and found answers. It had over heating problems before but not as bad as now. I did over heat it badly in June on a trip back from Sacramento to Auburn...long up hill all the way on a very hot day. It also used to back fire thru the carb before the new carbs were installed. Just dunno why the leak down would not have shown this ?

My 250 always showed hot on the gauge, 220 +, I didn't have a heat gun to check at that time so I was careful about driving it to hard. It would idle around 190 or more with a 180 t-stat. I moved the temp probe from the head to the thermostat housing, right under the thermostat. The gauge now reads 180 +or - as the thermostat regulates. The original hole location was right between #1 and #2 cylinders and the probe was picking up head from the cylinder chambers. I don't care what the water temp is deep in the engine, as long as what comes out of the thermostat is right, all is good.

You might consider moving the temp probe and giving it a try.

Joe

temp sender is not long enough to make it all the way up to the thermostat. "mechanical" after driving just around town. temp at the thermostat is at or above 215. to hot in my opinion.

You have repaird or replaced all things tht control the heat now you need to go after what creates the heat.as mentioned be fore, pull the head , check for warpage, cracks, check the block deck for the same.check all coolant passages in the block for blockage, ie debris build up in ports that feed head etc.Also make sure you have the corrct head.

Quindel54 makes a good point that I hadn't thought of. If the block and head are mismatched, the water passages could be partially blocked because of misalignment of the two. Don't know for sure if that's possible, but since you already need to pull the head, I would verify the part numbers on both the block and the head.

Sometimes shade tree mechanics do some strange things. Who knows what's gone on with that engine before Dogface got it?

One more for the list, pull a freeze plug or more to really flush out the block. Did this with a nice low mileage car years back and the darn block was packed with rusty crud, was quite a job just digging and flushing it all out.

Bingo....we have a winner. Just up at the shop when Joe pulled the head. Not only are the coolant ports clogged with major crap but apparently the head and the block are mismatched. There are two major 1"+ dia. ports between cal 1-2 and 5-6 which have no matching ports in the block.... I can't even believe some one would do this !!! Now I must find the proper matching head with valves etc. to put on this motor. I think the block is from a 57 car...who knows about the head...where to find one ?

http://s1276.photobucket.com/user/Dusty411/media/235block_zpse816d929.jpg.html?sort=6&o=0

Post some casting #s here. Someone can help identify. Glad you finally found the problem.

Pic just added to my last post...and this one. You can see between cal 1-2 and 5-6 that there is no port where the gasket allows for one. I'll get the casting numbers ASAP

http://s1276.photobucket.com/user/Dusty411/media/235block_zpse816d929.jpg.html?sort=6&o=0

just curious to how long you had the vehicle and
how long you have been driving it prior to it heating up...

you can probably find a good running engine for
what it might cost to repair this one...

I bought it in Dec...when weather was cold. Only started noticing overheating problem when weather warmed up in May... You may be right about the whole new motor but where to find one ?

I believe this odd hole in the head gasket that appears to not match with the block is not uncommon. Gasket suppliers make one gasket that will work with all the variations of 235 motors. Check the numbers and the flatness of block and head.

That might be true, but the head has a port there...

number on block behind distributor f410a
number on head intake/exhaust side 3836848

as mark said. port in block but has those two ports in the gasket and the head????

848 is good head for 235, geti it magnifluxed for cracks I have had to ditch a cracked head. It still impotant to check for warppage of block and head esp after severe overheating.again get the block passages cleaned out, check it all out even if it cost abit, peace of of mind goes a long way.you will know what youve got good luck

I just studied the pics from my stock 216 when I pulled the head and it too had 2 holes in the head but no matching holes in the block. The old headgasket had holes in those positions as did the new head gasket but again, there are two holes in the head but no matching holes in the block.
Based on the crud that was built up those holes in the head are in the water jacket.
I'm the 2nd owner of the 49 3100 and to my knowledge the engine was 100% original (bareing normal wear & tear parts).

The built up crud in your head could be your issue but the two blocked off holes in the head probably are not the issue unless that was a major change between the 216 & 235 blocks.
Good luck
Dave.

The f410a number is not the block casting number. It should be as six or seven digit number. Look at this page - http://clubs.hemmings.com/chevytalk/GMHistory/cast.html

The block casting number should be on a machined pad directly behind the distributor. Your is painted over, so you may have to scrape the paint off to see the number.

Dave,
I was just wondering about that same thing...there's enough crud in the existing passage ways to cause a lot of problems...

Edit: Pre68 Dave will know.

I checked that number once a bit ago...don't remember it but found it was from a 1957 car...for what that's worth ?

You will find that all 1953-62 heads will interchange and that the holes you see are part of the manufacturing process to get the sand out after casting.

Wow Dave ! I KNEW you would have the answer !!!

Hate to say it but the 235 I have apart right now has the same coolant hole situation. It hasn't been apart in decades.
There is a small hole in the head opposite the blank spots on the block. I was sorely tempted to drill the block.

I did find that some of the smaller holes in the block and head were packed full of rust scale that had gotten caught and accumulated there. That would be more than enough to restrict flow and cause it to run hot.

I did remove freeze plugs and use a pressure washer to clean out the block. Have it on an engine stand so I could rotate it upside down and sideways. Got a fair amount of crap out but there wasn't as much as I had expected. The head seemed to have more scale than the block.

Jim,
I'm glad you did say it...it only serves to re-enforce what pre68 Dave said...not that he needs it. My block and head are packed with the same crud but the block is still in the truck. I'm hoping it can be effectively cleaned out w/o removing it. I do have a good pressure washer that I can take to the shop but not sure if that would be smart to use while the block is still in the truck. It will produce about 3000 psi though!

Thanks for the input

I would highly recommend a pressure washer.
The 1926 on my blog was packed with rust and crud. I spent too much time scrapping at it before I got out the pressure washer. That made quick work of it.
You will need to put corks in the push rod holes and the center pass side head bolt hole and the small hole next to it. That is where the rocker oil comes from.

Dogface, back when I did my old 56 just used a garden hose and coat hangar plus other tools to dig around with. With the head off and manifolds you'll be able to get to those freeze plugs on the side, easy to remove and replace. This would be what I call the cast iron colonoscopy! Have fun.

That...is a great line... Thanks for the input

Mark,

If the radiator will be out of the way, I'll suggest again that you remove the water pump and, through the opening in the front of the block, gouge out junk all the way to the rear of both sides of the block (using something like heavy gauge copper wire). Do this until you can spray at each rear side of the block and see the water coming back/out on the other side of the block. This is not so easy to do (from the front) on/in the higher/earlier/exterior water-pump blocks.

Then, after doing the above clean-out, again check all smaller coolant passages.

I have been able (with much work and patience) to clear out blocks this way (without removing block casting plugs).