Cleveland Thermostat

After taking the thermostat cover off I noticed my Pantera is missing it's thermostat!! No wonder it ran warm! So I'm not sure how to orient the new one. Looks like this is the bottom (??)

Josh, you are right on in every respect. That is a Cleveland T-stat, it installs "pointy end up". Down inside the engine block's water passage, below the T-stat, there should be a copper "orifice" in the block, looks like a freeze plug but has a hole in the middle. If that orifice is still there, just pop in the T-stat and rock-n-roll.

If the coolant recirc passage was not plugged, and the T-stat was missing, then yes, that is why your engine was over-heating.

There are a few ways to plug the coolant recirc passage. One common way is to replace the copper orifice under the T-stat with a freeze plug. This can be visually detected with the T-stat removed. Instead of replacing the orifice with a solid freeze plug, some owners install a strip of metal between the water pump and the "recirc" passage. When I have eliminated the T-stat, I tapped the recirc passage with pipe threads and installed a pipe plug. Finally, at least one of the aluminum water pumps on the market does not have a passage for the coolant recirc cast into its pump casing. You'll need to check for anything that plugs the recirc passage before you install your new pump. Another way to determine this without removal of the water pump is by filling the recirc passsage (hole in the orifice) with coolant until it is full, then loosen the water pump suction hose & allow the coolant to drain from the water pump, if the recirc passage drains, it isn't plugged.

your friend on the PIBB, George

JK,

It looks different because it's a high flow thermostat.

Michael

Actually Michael,

all Cleveland T-stats look like that, with the deep cup shaped body and the copper button on the bottom. If it doesn't have those feaures, it's not a Cleveland T-stat.

your friend on the PIBB, George

George, wouldn't it seem that if there was no thermostat that the engine would run cool. The thermostat holds water in the engine block until the water temp hits whatever the thermostat is rated for then opens to allow water to circulate back through your radiator.

Living in northern Minnesota, when your thermostat sticks open there is no question because you lose the heat in the car.

Unless the Pantera has some different system, I don't believe this will help his overheating situation.

Steve

George,

I have Cleveland t-stats that look like all the others with the small center, and they fit right and worked just fine. I bought the one shown as a high flow replacement.

I wonder what other inferior parts their feeding us guys here on the east coast!

Michael

Steve,

I think what happens is the coolant flows too fast and doesn't stay in the radiator long enogh to properly cool off.

Michael

The Cleveland's coolant system IS unique, that brass orifice beneath the T-stat regulates the amount of coolant that is recirculated through the engine during warm up, coolant flowing through that passage bypasses the radiator, it flows from the engine block outlet directly back into the water pump's suction. Removal of the thermostat allows coolant to recirc continuously through that orifice, even when the motor is warm, so a substantial amount of coolant bypasses the radiator and is not cooled. The cup shaped bottom of the Cleveland T-stat seats against the round orifice plate and plugs that passage, so the wrong T-stat, without that cup shaped bottom, also allows the same condition, the uncontrolled recirculation of coolant.

The design goal of the Cleveland engineers was quicker warm ups & lower emissions, so the Cleveland has the capacity to recirculate more coolant than a Windsor, this design required a method for shutting off the recirc passage after warm up. That is achieved with the special thermostat with the cup shaped bottom and copper button (which I think acts as a guide).

The "standard" looking T-stats that you refer to Michael are Windsor T-stats. This is a very common mistake, not just right coastal either, its a national epidemic. Parts guys have been handing out the wrong T-stat for Clevelands ever since 1970. If I had a dime for every wrong T-stat I've removed from a Cleveland motor, well, I would at least be able to fill my fuel tank once with premium. LOL

Normally the effect of a wrong T-stat isn't detected until the vehicle is taken for a long trip, has to climb a long steep grade, is operated in a very hot (desert) climate, is raced, operated in stop & go traffic, etc. The Cleveland will operate fine with the wrong T-stat on short trips.

You guys are probably thinking right now "this guy reads too many tech manuals!" LOL

Your sleepy friend on the PIBB, George

Thanks for the info guys!!

What started this "journey" is a sudden overheating problem followed by a blown hose underneath the car (my guess from the pressure being built up in the system). After not having any cooling problems for years, the car suddenly started to overheat, and quickly! At first I go for the easy fix and suspect the T-stat, so I pull the cover off and WTF! No T-stat!! Since the rad is fairly new, my next target is my original water pump! This must be "it" since the radiator never got warm while the car overheated. Though I never heard any bearing noises or anything else out of the ordinary to point me to the water pump.

George, I'll take a pic of the area beneath the t-stat and post later today. Excellent info. Thanks again!!!

Josh

Definitely some great info, George. You learn something new everyday!

Michael

This is great timimg as I was just going to change my thermostat. I was aware of the Windsor/Cleveland thermostat issues and told my parts counter guy to make sure he gave me a correct 351C stat. The thermostat that I was just going to put in looks different than the picture posted. I bought NAPA # 297. Does any one know if this is the correct thermostat or does any one have a specific part # and manufacturer for the thermostat as well as a temperature reecommendation? Thanks. Vince

Vince,

I'm not familiar with the NAPA part, so I'm not able to help you there. Compare it to Josh's picture. It should have the deep, cup shaped bottom with the copper button in the middle. The thermostat has to be designed to mate with the brass orifice below it & plug the hole.

For a test, you can put your T-stat in a pot of boiling water & see what it does when it opens. Some part of the thermostat must extend downward to plug the orifice.

Flow Kooler sells Robertshaw thermostats via their web site, they are a reliable recommendation. The part number is 333, and is available in either 180 degree or 192 degree versions. Some people cringe at the Flow Kooler prices.

your friend on the PIBB, George

I also really appreciate all of the tech info you experts post here. I don't have any cooling problems now, but I'm sure it's just a matter of time. At least now I know a lot more about how the Pantera system differs from what I would have otherwise thought. Thanks again guys!

Once again George you have come through with the answer. If we ever meet in person, I owe you a drink. Vince

While I have the thermostat out,isn't there some kind of brass washer that is supposed to be mounted in the block already? I thought I read earlier that there is some kind of flow restriction there but in reality it's necessary. Since my car is over 30 years old it's safe to assume some one has been there before who might have thought it was better to remove this thing. What exactly should I be looking for. Thanks again.

Vince, you're welcome & it would be my honor to share a drink with you some day! I enjoy being able to help.

I forgot to bring the digital camera home from work tonight, I was going to post some pics, I have a spare block in my garage (imagine that! LOL). But for now, I'll try to describe the orifice in writing. I'm not as good at writing as my friend Ron though (very fast Italain). Looking down the hole below the thermostat you should find a round casting down inside the coolant passage, the casting is machined in the middle. Pressed into the middle of this casting should be a round, flat brass orifice that looks like a freeze plug with a hole in the middle. The word "top" is normally stamped in the upward facing surface of this orifice. The orifice is made of brass, but it most likely wont be shiny, more likely it will be a brown color.

Hope that helps.

Your friend on the PIBB, George

Here's an 'in & out' comparison for you George and Vince.

The t-stat hole is the one in the upper right of each block with the two bolt holes.

On the left, the restrictor is in place, and on the right, there is no restrictor.

I hope this helps.

Michael

thanks Michael!

George

I assume we want the restrictor because it keeps the water from reciculating through the block and not the radiator and if my restrictor is gone what's the best way to fabricate or buy one? I don't recall ever seing one for sale or in a catalog.
If anyone wants to buy a Flow Kooler thermostat, I just called them and they don't have 180s in stock and it might be a while, maybe months until they get them back. They have 192s but I think most of us would need the lower temp application. They aren't that expensive. They were $12.00 Vince

quote:

Originally posted by Cyboman:
Here's an 'in & out' comparison for you George and Vince.

The t-stat hole is the one in the upper right of each block with the two bolt holes.

On the left, the restrictor is in place, and on the right, there is no restrictor.

I hope this helps.

Michael

Hey I never noticed it before but the cylenders are staggered on the block. Is that an optical illusion or am I seeing it right??

DeTom,

You're seeing it right. The cylinders are slightly staggered to allow for where each connecting rod bolts to the crank. Two opposing cylinders uses the same journal on the crank, so they bolt on side by side (or one in front of the other), hence the slight stagger.

Michael

Vince,

The orifice, restrictor, what ever you want to call it, is available from the auto parts store, and is necessary so the T-stat has something to seat against when its open. Plus as you wrote, it is a restriction that controls the amount of recirc when the motor is cold.

George

quote:

Originally posted by Cyboman:
DeTom,

You're seeing it right. The cylinders are slightly staggered to allow for where each connecting rod bolts to the crank. Two opposing cylinders uses the same journal on the crank, so they bolt on side by side (or one in front of the other), hence the slight stagger.

Michael

Thanks Michael. That makes sense now that I think about it.

So a siemeze block means what ???

A siamese block is one in which there is no gap cast between the cylinders in the block for coolant to flow completely around each cylinder. Siamese blocks are cast solid between the cylinders. This is done to give the block more strength (less flex), but they usually run hotter because there is less coolant contact around the cylinders. The siamese moniker comes from the cylinders being connected together.

Michael