Hot Under-Hood Temps

[Big Red Mach 1]

Is it me or are these Clevelands very hot running engines? Not boiling over/ obvious problem type hot, just damn hot in general. Assuming I'm not alone, what have you guys done to help lower the temps under-hood?

I definitely wish I had blocked off the exhaust into the intake. I feel like that was a huge mistake that I made when I had the intake off and was re-sealing it. I will definitely block it off when I swap this intake for a Blue Thunder. Even with a 1/4" spacer, the carb gets extremely hot. 

I have Hooker long tubes. I wish the previous owner had opted for ceramic coated, but he didn't. I may end up purchasing a set of those. They say 30% lower temps with those. Would you all agree? 

Even though I don't boil over, I'm not confident in the current cooling system. My gauge always reads low regardless. I don't trust it at all. My fan clutch is constantly engaged because the radiator gets pretty hot almost immediately after start-up. I'm thinking about buying a Champion aluminum radiator. I have a new T-Stat and bypass plate coming from T-Meyer.  

My current thought is that this old radiator is partially restricted, or I don't have the bypass plate installed. Neither would surprise me. 

The heat transfer is insane. Even my strut tower braces get hot enough within minutes that you definitely don't want to touch them. I'm assuming that's from the header heat coming straight up. 

Anything else you guys can suggest while I build my shopping list?

 

[Don C]

Header wraps will do more than ceramic coating

https://www.summitracing.com/search/department/exhaust/section/heat-protection/part-type/exhaust-wrap?SortBy=Default&SortOrder=Default&autoview=ProductName&utm_source=bing&utm_medium=cpc&utm_term=header+wrap&utm_content=Exhaust+Wrap&utm_campaign=General+Terms+D+-+L

 

[Big Red Mach 1]

Thanks Don, I've seen the wrap before, but didn't know how well it might work. I'll definitely take your word for it. : )

 

[Don C]

The down sides of it are it's not very pretty, although DEI makes a silicon black spray coating, and it can hold moisture in and cause early rust-out on uncoated headers. Making sure they get warmed up enough to boil off any moisture helps, if you get caught out in a rain storm.

 

[Big Red Mach 1]

I live in Arizona. Two things we don't do...Rust and rain. : )

 

[Bill73Ragtop]

"My current thought is that this old radiator is partially restricted, or I don't have the bypass plate installed. Neither would surprise me. "

Running without restrictor will result in high engine temps. Obviously get the radiator checked and if needed, repaired / replaced. Make sure you have the correct cleveland thermostat.

My experience is properly built Clevelands run cooler than big blocks and a lot of small blocks.

 

[Canted 393]

Run this for a waterpump, I am running this on my 525 hp, 393C stroker and it runs 180 all day long.

https://www.summitracing.com/parts/bra-1648/make/ford

 

[jpaz]

My Cleveland runs at 180 all day too. I have it bored .040 over std. and have no heat issues. But I do have a new radiator and water pump with a 180* thermostat. I also put some black ceramic coated hooker headers on and I think they actually run cooler than the stock manifolds. I drove it last week when it was 92* outside with no overheating problems at all.

 

[Stanglover]

My thoughts why it's running hot.

1) headers. I don't have them on this car, but did on a previous Mach 1 and it was always hot under the hood.

2) inefficient rad. If you want to keep it some what original, get the rad re-cored to at least a 3 core. That made a huge difference on mine.

3) incorrect T stat. There are lots of supposedly correct stats out there, but some are not totally correct and don't seal off the by-pass plate.

4) Exhaust cross-over passage on intake. This was intended to warm up the Autolite carb which was designed for it. Aftermarket carbs are not. You can do a quick block off by carefully (drilling if needed) tapping for a 5/16" set-screw in the corners of the carb base opening. Not sure how to describe that, but I think I have a pic. On mine, I had a whole lot of problems with fuel boil-off evaporation until I physically blocked off the cross-over and added a 1" fiber spacer. Also, without stopping the hot exhaust in the cross-over, you could burn the base of your new carb. The original base gasket has a metal plate inserted between the 2 layers of gasket material. I suggest using one of those anyway.

One more thing, I inserted a small piece of .020" SS into the intake paper gasket to add an extra block-off over the cross-over holes on the heads. No pic, sorry. If your changing to the Blue Thunder, this all may be irrelevant.

5) Timing, but I doubt that is the problem now.

After a long run on a hot day, I got in the habit of opening the hood and letting it cool down before putting the car back in the garage because, being only a one car garage, it gets very hot in there if I don't..... unless it's raining, then it goes straight in!!

Here's a couple of pics,



two hole in corners where I tapped and inserted 5/16" set screws. Use grease on the tap to stop cuttings dropping in.



 The block-off is made from 1/16" SS and set on a hand milled step, then stitched and sealed with exhaust cement, pic below.



EDIT;

Jpaz mentioned a 180* T stat, and his car runs at 180*. I use a 195* stat, but gauge shows about 185* running. It will go way up if a get stuck in traffic on a hot day, but cools down quickly once moving again or by revving the engine.

 

[tony-muscle]

It probably is a combination of what these guys are saying. I have ceramic coated headers, a manifold with plugged bypass, new Champion radiator and a 195C thermostat. The engine bay doesnt feel hot after driving. I can touch anywhere except the engine and i dont get burn. The engine temp is between 195 and 200 while running. The oil temp is at 180-190.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[Carolina_Mountain_Mustangs]

I have had 351 C Q code since 1973 never had heat issues and parked that car for years. I have 8 Mustangs with 351 C engines H or Q. 

I saw your statement that you had ordered the plate from Mayer to do the thermostat change. I would not do that. The factory baffle works fine and I never heard of heat issues ever until recent years. 

I always run a 192 deg. thermostat. Yes there is a unique thermostat to the Cleveland the old versions had like a hat on the end of the plunger. That hat goes into the hole in the restrictor plate in the block.

When at an Advance Auto store I had him pull a thermostat and it looked to be correct just the plunger went into the restrictor plate with no hat on it. I had found a few of the old style at an old close parts store and bought them all. 

Since you are newer to the forum I will repeat this info on a 73 I bought off of Ebay few years back.

I bid and won a 1973 Mustang convertible in California. The owner said he had his race team build the engine and he took the car to his Reno summer home but never drove it for 25 years. I thought that was odd and kept asking questions. 

So I got the car to N.C. and it sat for two more years while I built garage. Since the car had sat so long I had to change master cylinder and I just cleaned the all new brakes he had put on. I pulled the valve covers and inside the motor was all new so I only pulled the thermostat and put the 192 deg. in.

I got the car running the night before a car show in town about 8 miles away. So I got up and drove the car to the show. I use a 50% antifreeze and 50% distilled water mix. The factory center gauges showed the car was almost to the Hot side and I pulled into the line and turned the engine off. When I got out and opened the hood the radiator cap released pressure and blew out some coolant. I had fixed sever 289 & 302 Ford engines that were doing that in the past. That is a sign of the head gasket being backwards. On the 289 302 you can knock the core plug out of the front of the head and feel if the gasket is right or not. 

The Cleveland head does not have the core plugs but the head gaskets are cut different in the front and back bottom corners. The front corner is almost square and the rear has a big radius and angle. I looked with a mirror and his pit crew had installed the R.H. head gasket backwards. I pulled the heads and for sure was backwards. You get a little bit of flow when backwards but coolant is trapped in the head causing a hot spot. It will not boil when going down the road but when you turn the engine off that hot spot boils the coolant and blows it out. 

With the heads off I could see the pistons were brand new and were marked .050" over. I think he figured he had bored the block too far was what the heat issue was and he just parked the car for 25 years. After the head gaskets were right It does not heat up and have driven over two hundred miles and over 90 deg.. Also took to a rod show in Tenn and the traffic was stop and go for miles and no heat issues. The car has AC, PS and still no issue. It also has flat top pistons, cam, long tube no coating or wrap headers, Holley 4-2 on 2-V heads Edelbrock performer intake and cam that I do not know spec on.

He had taken the FMX out and put in a C-4 with shift kit. I went ahead and put a Hayden fan cooled transmission cooler on the car. The radiator is an original Ford for AC not oversize. 

If you take a mirror and look at your head gaskets to check for backwards. They are clearly marked FRONT but happens a lot. The logo that Fel Pro is on the top of one but on the bottom of the other. I think people put the logo up and think it is right but one will be wrong.

I would not install the Mayer kit you can pull your thermostat in 10 min. and see if it has the baffle in place and check for correct thermostat. 

A 195 deg is also good to use. Here are some pics of the old style with the hat on the end and the new style that the plunger just goes into the baffle. One on left is old Stant 192 and one on right is a current style 195 deg. either will work fine. Notice in the side view the length of the thermostat has to go deep enough into the block so the plunger or hat goes into the baffle. One big reason to use the higher temp. is to keep the water in the radiator longer to allow it to cool. If you were to pull thermostat out if will for sure run hot nothing to slow the water flow down. 

Also a pic of Cleveland head gasket like it will be on the drivers side. The round hole in the tab on the top of the 351 C goes to the front of engine.

There is absolutely no reason to run hot if you have correct timing, right thermostat, baffle in block and a clean radiator. BTW some radiator hoses do not have spring inside to prevent collapse when under suction from water pump. If your hose is just rubber get a spring in it or replace with hose with spring. To check it just squeeze it. 

 

[Big Red Mach 1]

Ordered the following;

Champion 3 Row Radiator

New T-Stat and Restriction Plate from TMeyer

Billet T Stat housing

Ordered the water pump as suggested by Canted 393 above

I went with new ceramic coated headers over the tape.

Ordering Port plates for intake and exhaust that will give better flow and also block off the exhaust passages to the intake.

I already have a Blue Thunder intake on it's way.

My Amex bill is going to be up there this month. Good thing I pay it or the wife would have a heart attack. LOL

 

[Big Red Mach 1]

I have had 351 C Q code since 1973 never had heat issues and parked that car for years. I have 8 Mustangs with 351 C engines H or Q. 

I saw your statement that you had ordered the plate from Mayer to do the thermostat change. I would not do that. The factory baffle works fine and I never heard of heat issues ever until recent years. 

I always run a 192 deg. thermostat. Yes there is a unique thermostat to the Cleveland the old versions had like a hat on the end of the plunger. That hat goes into the hole in the restrictor plate in the block.

When at an Advance Auto store I had him pull a thermostat and it looked to be correct just the plunger went into the restrictor plate with no hat on it. I had found a few of the old style at an old close parts store and bought them all. 

Since you are newer to the forum I will repeat this info on a 73 I bought off of Ebay few years back.

I bid and won a 1973 Mustang convertible in California. The owner said he had his race team build the engine and he took the car to his Reno summer home but never drove it for 25 years. I thought that was odd and kept asking questions. 

So I got the car to N.C. and it sat for two more years while I built garage. Since the car had sat so long I had to change master cylinder and I just cleaned the all new brakes he had put on. I pulled the valve covers and inside the motor was all new so I only pulled the thermostat and put the 192 deg. in.

I got the car running the night before a car show in town about 8 miles away. So I got up and drove the car to the show. I use a 50% antifreeze and 50% distilled water mix. The factory center gauges showed the car was almost to the Hot side and I pulled into the line and turned the engine off. When I got out and opened the hood the radiator cap released pressure and blew out some coolant. I had fixed sever 289 & 302 Ford engines that were doing that in the past. That is a sign of the head gasket being backwards. On the 289 302 you can knock the core plug out of the front of the head and feel if the gasket is right or not. 

The Cleveland head does not have the core plugs but the head gaskets are cut different in the front and back bottom corners. The front corner is almost square and the rear has a big radius and angle. I looked with a mirror and his pit crew had installed the R.H. head gasket backwards. I pulled the heads and for sure was backwards. You get a little bit of flow when backwards but coolant is trapped in the head causing a hot spot. It will not boil when going down the road but when you turn the engine off that hot spot boils the coolant and blows it out. 

With the heads off I could see the pistons were brand new and were marked .050" over. I think he figured he had bored the block too far was what the heat issue was and he just parked the car for 25 years. After the head gaskets were right It does not heat up and have driven over two hundred miles and over 90 deg.. Also took to a rod show in Tenn and the traffic was stop and go for miles and no heat issues. The car has AC, PS and still no issue. It also has flat top pistons, cam, long tube no coating or wrap headers, Holley 4-2 on 2-V heads Edelbrock performer intake and cam that I do not know spec on.

He had taken the FMX out and put in a C-4 with shift kit. I went ahead and put a Hayden fan cooled transmission cooler on the car. The radiator is an original Ford for AC not oversize. 

If you take a mirror and look at your head gaskets to check for backwards. They are clearly marked FRONT but happens a lot. The logo that Fel Pro is on the top of one but on the bottom of the other. I think people put the logo up and think it is right but one will be wrong.

I would not install the Mayer kit you can pull your thermostat in 10 min. and see if it has the baffle in place and check for correct thermostat. 

A 195 deg is also good to use. Here are some pics of the old style with the hat on the end and the new style that the plunger just goes into the baffle. One on left is old Stant 192 and one on right is a current style 195 deg. either will work fine. Notice in the side view the length of the thermostat has to go deep enough into the block so the plunger or hat goes into the baffle. One big reason to use the higher temp. is to keep the water in the radiator longer to allow it to cool. If you were to pull thermostat out if will for sure run hot nothing to slow the water flow down. 

Also a pic of Cleveland head gasket like it will be on the drivers side. The round hole in the tab on the top of the 351 C goes to the front of engine.

There is absolutely no reason to run hot if you have correct timing, right thermostat, baffle in block and a clean radiator. BTW some radiator hoses do not have spring inside to prevent collapse when under suction from water pump. If your hose is just rubber get a spring in it or replace with hose with spring. To check it just squeeze it. 

I had already ordered the T-Stat and new restrictor from TMeyer. So that's already on it's way. I'll check the orientation of the head gaskets. Thanks!

 

[Don C]

You should be fine with the TMeyer t-stat and plate. The bypass plate from TMeyer functions the same as the original, the difference being that it is a machined part instead of stamped like the original. The thermostat is the same as the original Robertshaw, which is correct for 351Cs.

 

[Canted 393]

Since its fun to spend your money, take a good look at your timing cover to see if its corroded badly. Here is the replacement 1 I used on my 70 cougar, https://www.summitracing.com/parts/ses-5-65-04-201/make/ford

 

[Carolina_Mountain_Mustangs]

You should be fine with the TMeyer t-stat and plate. The bypass plate from TMeyer functions the same as the original, the difference being that it is a machined part instead of stamped like the original. The thermostat is the same as the original Robertshaw, which is correct for 351Cs.

I thought the Meyer changed it to use a normal thermostat. What difference would a machine part make over the stamping. That center hole would be within a few thousandths of an inch as a stamping.

I thought his idea was to eliminate the need for the C thermostat which is not extinct just looks different like the one in my pics. He was working on heat issues in a Pantera that is totally a different animal for sure. How do you spell that?

 

[tony-muscle]

You should be fine with the TMeyer t-stat and plate. The bypass plate from TMeyer functions the same as the original, the difference being that it is a machined part instead of stamped like the original. The thermostat is the same as the original Robertshaw, which is correct for 351Cs.

I thought the Meyer changed it to use a normal thermostat. What difference would a machine part make over the stamping. That center hole would be within a few thousandths of an inch as a stamping.

I thought his idea was to eliminate the need for the C thermostat which is not extinct just looks different like the one in my pics. He was working on heat issues in a Pantera that is totally a different animal for sure. How do you spell that?

TMeyer's thermostats are designed to be used in standard Clevelands with the bypass plate. They still have the small "cup" at the bottom. His are the same design as the Robertshaw ones since he is using the same molds. He sells a machined bypass plate separately. I assume he machines it because it is more cost effecting for small number runs.

https://www.tmeyerinc.com/product/high-flo-thermostat/

 

[Don C]

West Coast Classic Cougar sells the block-off plate, based on feedback from Pantera owners, most of whom had heating problems because of using the wrong thermostat. They had to drill a hole in it so that air could escape from the block.

If you're interested there is more information here

https://www.7173mustangs.com/thread-351c-cooling-system?pid=215259#pid215259

 

[Big Red Mach 1]

Hope you are all well, staying safe, healthy and wearing your masks when needed. Sadly, out here in Arizona, many didn't choose to listen to the doctors and scientists, and we're the current hot spot in about 3 different ways out here now. 

Finally got some time with the car again. First thing I did was block off the exhaust ports in the my new Blue thunder intake. I'll be glad to keep more heat away from the carb. Pretty much did it just as Stanglover suggested. I used 1/8" thick 304 Stainless for the plates and used the High Temp JB Weld for smoothing and gap fill. Photo is from BEFORE the JB Weld filled the gaps. I'm happy with it.