Coolant does not flow with thermostat installed

[Stanglover]

From reading your replies, all I can say is wow!!!! This has to be very frustrating to say the least. You want to be out enjoying your car and then there's this problem, keeps on going like the proverbial E Bunny.

Did you have a look under the car for water along the frame and underfloor? It might be from the overflow tube, indicating that is where the water is going. You could used a plastic bottle on the overflow tube to see if it does collect some water from the tube.

If you had the rad checked off the car. it would be easy to see if water flows through correctly, proving it's not blocked. I don't know what else to suggest. There are many far more experienced members than am I and if they can't solve it???!!!

Anyway, hope you get to the bottom of it soon, keep us posted,

Geoff.

You were typing at the same time I was. Can you tell us exactly what T stat you are using, brand and number. NPD sells a so-called Cleveland stat , but IT"S NOT!! it's a Windsor or something. It does not have a HAT on it. I bought a STANT 13468 and 69 and have zero issues. I'm currently using the 13468 180 deg. If you don't have the correct stat, I'm guessing you WILL have problems.

I had taken the radiator into the shop and asked them to go through it. They said the found very little debris in it, and the radiator is not my issue.

I am using a motorcraft t stat supplied by west coast classic cougars.

it is for a 351c, 180 deg.1967-1973 mustang. However, it is not the hat design. I am using it in conjunction with the bypass restrictor plate that I purchased from WCCC. With the restrictor plate you don't use a Cleveland type t stat.

I'm thinking of trying to research and find an original brass restrictor plate and the correct thermostat.

Thanks for clarifying the stat you are using and that your rad is good. One more tick on the good list!

I would think others have used this stat & restrictor combo and can

comment. If, by elimination, everything else is good, then perhaps this is not working for the Cleveland and you can go back to the original design. Clearly you are a very competent person and you will solve this mystery.......soon.

Personally, I am finding this post very useful for my own experience and knowledge and I have enjoyed offering what I can and reading other comments. That is why I joined the forum, problem solving in a friendly atmosphere. I hope you find the same thing.

All the best getting to the bottom of this annoying problem.

Geoff.

 

[rocket366]

Still wondering if the cooling system is being pressurized by exhaust?

You should do the look for exhaust bubbles test I mentioned earlier that would explain the coolant loss out the overflow.

There sounds like there is still an issue with the T Stat/Restrictor post a photo of that.

Hope its somthing simple like T Stat installed upside Down. (sorry for that but U never know)

Good Luck

Paul

 

[klinton994]

Still wondering if the cooling system is being pressurized by exhaust?

You should do the look for exhaust bubbles test I mentioned earlier that would explain the coolant loss out the overflow.

There sounds like there is still an issue with the T Stat/Restrictor post a photo of that.

Hope its somthing simple like T Stat installed upside Down. (sorry for that but U never know)

Good Luck

Paul

Rocket,

I have not seen any bubbles rising from the bottom of the radiator.

the T stat is installed with the spring into the block.

Earlier today, I pressure tested the system when the gauge on the dash indicated it was in operating temperature.

I put 16lbs of pressure into the system. I just a couple of minutes the pressure increased to 21 lbs. When I increased the rpm's, the pressure dropped back to 16lbs. I don't know if this means anything or not.

It appears I have two issues. Disappearing coolant, and little flow from the thermostat.

 

[rocket366]

No Bubbles is great news!!!

Back in the day my Stant cooling system pressure checker would also test radiator caps by means of an adapter and perhaps

your cap is just letting the coolant out at low pressure? A temporary catch bottle would test for that.

I know this is frustrating but it seems we are back to the T Stat. If you have circulation like you say without it.

You need to post a photo of the T Stat/ Restrictor combo for us to go further I think?

Paul

 

[justford]

Losing that much coolant with no visible signs is a head scratcher. Have you had someone follow you on your drive to see if they notice anything coming from the exhaust pipe? The knocking noise is also a concern as we all know what we usually associate that with.

 

[klinton994]

Losing that much coolant with no visible signs is a head scratcher. Have you had someone follow you on your drive to see if they notice anything coming from the exhaust pipe? The knocking noise is also a concern as we all know what we usually associate that with.

The knocking noise only appears after the motor is warmed up, and there is no rhythmic pattern to the noise. I've not seen any coolant come out of the overflow tube after driving and allowing it to idle, or after turning off the motor.

I have surrendered to the belief that I may indeed have a failed head gasket or cracked head.

 

[Don C]

A couple more thoughts, does your WCCC restrictor plate have a small air relief in it? If not, or if it is plugged, air will be trapped, which will cause overheating. Your symptom of the knocking sound is typical of an engine boiling when a t-stat does not open, fills the block with air bubbles, and forces coolant out of the lower hose against the flow of the water pump.

A fully open t-stat will not flow as much coolant as with no t-stat.

 

[rocket366]

I think Don nailed it^^^

A blown head gasket, cracked head/block you would see steam out exhaust or the bubbles

that rise to the top of the radiator that pop and release exhaust.

 

[Bill73Ragtop]

Engine knock is also the indicator of a head gasket installed incorrectly (backwards). Usually you hear the knock as soon as you shut it down.

 

[Stanglover]

Klinton, re-reading your first post, it seems you have already done almost everything that has been suggested several times. I have no experience with anything other than stock, but Don's suggestion about the restrictor plate either not having a hole in it (unlikely) or plugged makes sense to me. If it were me, I'd go back to a stock restrictor plate and t-stat before ripping into the engine. I think you could find a stock plate on e-bay.

In post #20, I suggested pressure testing the block hot with plugs out. If you have a remote engine start button, (or have someone crank the motor) you could look for signs of water out of a plug hole if there is a small gasket leak that is not noticeable cold. However, I think from reading all the posts, this is unlikely but may still be worth checking.

If I had any hair, I'd be bald by now. Frustrating or what!!

 

[justford]

I guess I am focused on the adding a gallon of coolant without any visible signs of leakage. Figure out where it is going and you will find your problem(says captain obvious).

 

[Stanglover]

Did you see the info in post # 17 - 351C cooling system?

 

[BeerDontCount]

It seems to me we are over thinking this one. If it flows without the thermostat, but doesn't when its installed, then it stands to reason that the thermostat isn't opening when it should. Why it would bench test ok, but not work installed, I don't have an answer for, but my best guess is that its blocking at the t-stat. The loss of coolant could possibly be explained by the lack of an overflow tube with the rising pressure expelling more than it normally would. Might be something else going on as well, but to me it seems that the main problem is the thermostat. My two cents.

Scott

 

[klinton994]

A couple more thoughts, does your WCCC restrictor plate have a small air relief in it? If not, or if it is plugged, air will be trapped, which will cause overheating. Your symptom of the knocking sound is typical of an engine boiling when a t-stat does not open, fills the block with air bubbles, and forces coolant out of the lower hose against the flow of the water pump.

A fully open t-stat will not flow as much coolant as with no t-stat.

Don,

I will look again at the restrictor plate. It did have a small hole in the center. Would it be o.k. if I increased the size of small bleeder hole in the center of the plate be. Perhaps going up only one or two drill bit sizes?

 

[klinton994]

I guess I am focused on the adding a gallon of coolant without any visible signs of leakage. Figure out where it is going and you will find your problem(says captain obvious).

At this time, my cooling system is probably 98% water. Although it is a closed system, could the water be hot enough to dissipate within the system, and require the daily filling?

 

[rocket366]

the hole in the factory restrictor plate is abt 3/4 inch if I recall correctly or perhaps larger.

I'm running a Windsor T Stat with stock restrictor with no issues with stock radiator and flex fan however I would like

to find the cleveland stat.

Paul

 

[Stanglover]

the hole in the factory restrictor plate is abt 3/4 inch if I recall correctly or perhaps larger.

I'm running a Windsor T Stat with stock restrictor with no issues with stock radiator and flex fan however I would like

to find the cleveland stat.

Paul

Not to go off topic too far, but you can easily get a Stant 13468 or 13469 from RockAuto for about 5 bucks each if I recall, which is a Cleveland specific t-stat. Other brands are available, but this is the one I got. Currently using the 13468 180 deg. The restrictor hole is about 3/4", but the 'hat' diam. is only about 5/8". Apparently this is a normal diameter.

As for the flex fan, lose it. They are dangerous and not very efficient at high rpm's. Several years ago, I worked making prototypes of automotive engine components, fans being one of them. If you ever saw the damage a flex fan can do WHEN (not IF) it blows up, you wouldn't want to be within a mile of it. Believe me, they can take your head off.

 

[Stanglover]

I guess I am focused on the adding a gallon of coolant without any visible signs of leakage. Figure out where it is going and you will find your problem(says captain obvious).

At this time, my cooling system is probably 98% water. Although it is a closed system, could the water be hot enough to dissipate within the system, and require the daily filling?

We know you're going through a lot of water, but wouldn't just plain water cause the engine temp to be higher as it boils at a lower temp compared to Prestone or similar even under pressure? It would be costly to keep adding coolant I know.

 

[Carolina_Mountain_Mustangs]

I would go back to the factory style restriction and cleveland thermostat. I think I recall you saying that the temp gauge never really shows hot which seems odd. For you to blow the water out the radiator cap has to be opening. I recall that you had it tested and it was ok. If you have another one I would try it.

You should not just run water in the system it will rust the cast iron pieces like crazy and tough on the water pump seal. I would also suggest you use distilled water in the mix to eliminate any build up of minerals in the radiator that will cause issues later. I know you don't want to put antifreeze in it and just blow it out.

Do you know anyone who has one of the blown head gasket testers you put on the radiator filler. You put a liquid in it and run the engine and it changes color if there is a leak. Google it there will be a video showing it I am sure. I know you checked before but this finds even the smallest leak. I still suspect a head gasket with you blowing the water out as much as you are.

My Ford truck has never had coolant added or changed since new in 2002 and it has over 250,000 miles never a hose or anything, knock on wood.

Blowing water out of the system is not normal for sure. Head gasket or radiator cap if radiator checked out and thermostat is working would be the cause.

Just more food for thought.

 

[Don C]

A couple more thoughts, does your WCCC restrictor plate have a small air relief in it? If not, or if it is plugged, air will be trapped, which will cause overheating. Your symptom of the knocking sound is typical of an engine boiling when a t-stat does not open, fills the block with air bubbles, and forces coolant out of the lower hose against the flow of the water pump.

A fully open t-stat will not flow as much coolant as with no t-stat.

Don,

I will look again at the restrictor plate. It did have a small hole in the center. Would it be o.k. if I increased the size of small bleeder hole in the center of the plate be. Perhaps going up only one or two drill bit sizes?

It wouldn't take much to plug the hole in the WCCC plate, most of our cooling systems have stuff in them that would plug a hole that size, especially when yours has been boiling and knocking rust and scale loose. If you want to keep it I would try drilling it out some.