351 Cleveland Overheating Issued

Just rebuilt my 351 Cleveland have a TMeyer thermostat (180) new high volume water pump radiator is good, fan Shroud all good. The top hose does get as hard as a rock though. Runs around 205-210??

Does the block have the flow bypass plate in place?

Yes, restrictor plate is in.

Is the temp gauge, sender and cap known good?

Yes, brand new Intellitronix temp gauge.

You are running "Hot" not really "Overheating" at 205/210 degrees. 50/50 coolant mix cools better then pure (100%) coolant. Does it hit 210* in stop & go or highway? Check your timing and pull a couple plugs to verify your engine tune. Lastly, a fresh engine can run a bit hot.

Cleveland Crush said:

You are running "Hot" not really "Overheating" at 205/210 degrees. 50/50 coolant mix cools better then pure (100%) coolant. Does it hit 210* in stop & go or highway? Check your timing and pull a couple plugs to verify your engine tune. Lastly, a fresh engine can run a bit hot.

Click to expand...

I’m hoping it’s not a blown or cracked head gasket. The top hose gets awfully hard and very hot??

MattCoppola said:

I’m hoping it’s not a blown or cracked head gasket. The top hose gets awfully hard and very hot??

Click to expand...

Runs fine with cap off…

Is any coolant being forced out of the overflow?

Cleveland Crush said:

Is any coolant being forced out of the overflow?

Click to expand...

Not that I can see. Nothing on the ground

Further testing is needed to verify IF head gaskets are a problem: compression test, leakdown test and radiator exhaust gas test. All relatively simple to preform.

Got any pics of your setup and restrictor inside the block?

Cleveland Crush said:

Further testing is needed to verify IF head gaskets are a problem: compression test, leakdown test and radiator exhaust gas test. All relatively simple to preform.

Click to expand...

Those will be next steps. Thanks!!

Hopefully your head gaskets are oriented correctly

When I installed them I am 100% sure I put the openings toward the back of the engine. But now, I’m second guessing myself!!

I believe the head gaskets are self-explanatory, as there is a big square water passage at the front on both head and deck surfaces., on the Clevelands. Usually, when installed correctly, a small tab of a corner of the head gasket will be sticking out at the lower front corner of the head. The photos below show in the 1st picture (open the photo) with no square opening at top right of block, this is the left, or driver's side, and the square opening is just out of frame to left. 2nd photo clearly shows right side of block with square water opening. You can hardly get these gaskets on wrong. Back when I was doing service work, if a customer came in with an overheater, amongst all the things we would do to check, was bring the vehicle up to temp with the cap off and put a thermometer in the radiator coolant to double check the gauge. It's usually a combination of radiator, water pump , shroud, thermostat, gauge, coolant mix, radiator cap, timing check, while looking at the system. Of course, a block at .060" over can heat up too.

MattCoppola said:

When I installed them I am 100% sure I put the openings toward the back of the engine. But now, I’m second guessing myself!!

Click to expand...

The head gaskets are marked with FRONT. One gasket will appear to be upside down, compared to the other. This has tripped up more than a few not familiar with the cleveland. Another telltale that a gasket is on backwards, is gurgling sounds coming from the engine.

Also, make sure the lower hose isn't collapsing.

Does it run hottest when stationary or when running at highway speeds?

How much was the block bored oversize?

Did you have it sonic checked as well for cylinder wall thickness?

The radiator hose getting firm, does it do that when you crank the engine up cold, or only after it warms up?

And what happens when you run the engine with no radiator cap? Whatever was pressurizing the hose should come out the radiator opening. Is it coolant or is it combustion gases?