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Bad News for my 1965 Mustang

9K views 66 replies 38 participants last post by  evantugby 
#1 ·
Gents,
I'm afraid I have bad news. I recently purchased my 1965 Mustang 289 4V from Helena Montana and brought it to San Antonio Texas and I cannot get it to stay cool. New radiator, new thermostat, timing and carb adjusted, new radiator hoses all done by seasoned vintage mustang Mechanics at Alamo Classic Ponies, here in San Antonio. They have determined it is not the fault of the cooling system but instead discovered my engine is producing to much friction causing the thermostat to remain in the open position allowing water to constantly flow from the engine to the radiator and back into the engine again before the fluid has had an opportunity to cool down in the radiator.

They now believe it could be the following: 1. The engine may have been overbored to .060 or 2. internal engine components have been scorched due to overheating one to many times.

They are getting me prices on two options:

1. new crate engine (recommending 5.0L 302 engine)
2. pull engine from car and rebuild.

QUESTION: Has anyone else experienced this specific issue dealing with an engine that could not stay cool because of something other than a bad cooling system? If so, what do you recommend?
 
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#3 · (Edited)
I'm running .060 over with the 302 in my F150 and it runs perfectly ok and does not over heat. However, my shop sonic checked the cylinders and verified I still had enough material to bore it .060 without causing any problems. You should try and verify if the block was checked similar to that before being bored.

Look at the tabs on your head gaskets under the heads. You should be able to tell if they are installed correctly or backwards or possibly one is backwards which would make your engine run hot. This happens more often than you might expect. I almost did it myself on my new build.

See in the photo, one end has coolant passages and the other, closed off end has a squared tab on the lower corner of the gasket. The other end does not. The 2 large coolant openings on the end of the gasket go to the back of the block.


Aside from all that, how hot is it running? What temperature thermostat did they install in it?
 
#6 ·
Look at the tabs on your head gaskets under the heads. You should be able to tell if they are installed correctly or backwards or possibly one is backwards which would make your engine run hot. This happens more often than you might expect. I almost did it myself on my new build.

See in the photo, one end has coolant passages and the other, closed off end has a squared tab on the lower corner of the gasket. The other end does not. The 2 large coolant openings on the end of the gasket go to the back of the block.
This was my first thought while reading the 1st post. If the engine isn't losing coolant, then that rules out a leak somewhere, either external or internal. Check the placement of those head gaskets...been there, done that.
 
#4 ·
I just don't buy the .060 overbore as the cause of overheating.
If your engine is overheating it means that the heat generated is being effectively transferred to the coolant, but the cooling system is, for some reason, not able to dissipate that heat.

Your shop is suggesting a pretty extreme course of action to fix the problem. I think you should by absolutely sure there isn't an easier fix before you spend that kind of money.
 
#5 ·
If they have a bore scope they may be able to find a piston size or just tell you how carboned up the pistons are !
 
#8 · (Edited)
Who is Helena Montana or is Helena a town? JK. Do you have confidence in the mechanic? Sounds like he came to some conclusions as to cause with very little data. Strange recommendation no 2 is rebuild engine when
one assumption is it's been overbored too big already!!! I recommend having a
added opinion from a mechanic trying to solve the problem rather than sell engine or rebuild! JMO. So called overheating is one of the most frequent posts on VMF. Never saw "pull and replace whole engine or rebuild"!!!!!
 
#9 ·
When you say it's overheating, can you provide a tad more information.

Is there a temperature gauge that accurately reads your water temp?

What temperature is your car running?

What is the condition of your radiator cap and what pound is the cap rated for.

Is your system puking coolant?
 
#20 ·
Original temperature gauge was at the "H" on the dash. My fan shroud got so hot it collapsed on itself and essentially melted and warped. The car has been tested with a laser dot temp reader and its very hot, I think 250 degrees. Radiator cap and radiator are 2 months old (aluminium 2-row radiator). Yes my car is puking coolant into the overflow reservoir, boiling hot...so hot the plastic cap on the overflow reservoir melted.
 
#10 ·
They have determined it is not the fault of the cooling system but instead discovered my engine is producing to much friction causing the thermostat to remain in the open position allowing water to constantly flow from the engine to the radiator and back into the engine again before the fluid has had an opportunity to cool down in the radiator.
The bad news is, you need a mechanic that understands how cooling systems work. These guys clearly don't, so I suggest you start there.

Sincerely,
MrFreeze
 
#13 ·
What kind of fan are you running? Do you have a fan shroud? As mentioned, there isn't a need for a new engine or anything drastic like that just because of some overheating.

Some specific numbers might be helpful, what temp is the car running at now? What temp are you shooting for? I would be skeptical of any work performed by that place if they recommended a new engine for this issue.
 
#22 · (Edited)
Full store: Purchased car in Helena Montana. Previous owner didn't notice an overheating issue. I towed it to Boise Idaho and drove it around for a week with no issue. While there I replaced the old R12 A/C and replaced with new R134A A/C. Did oil change, tranny flush, radiator flush and put the car into my trailer and towed it to San Antonio. The very first time I drove it it overheated. Car was running around 250 degrees. I would like it to stay around 190 to 200 degrees. The original engine temp gauge had the needle at the "H". Towed it to Ford Dealership. After three attempts to fix the overheating problem (costing me new radiator, new upper/lower radiator hoses, new thermostat, new fan shroud, labor cost to retime engine) they finally said they couldn't fix it and gave me a credit to take it elsewhere. Took it to Alamo Classic Ponies and they found that Ford installed the thermostat backward. We all thought that was the culprit. WRONG, still overheated. The car got so hot my brand new fan shroud melted and warped onto the fan. I was running a six blade belt driven fan. Alamo Classic Mustang Mechanic switched it out for a flex-a-lite engine fan and put it much closer to the radiator to get maximum air pulled through the radiator. Still overheating. They literally watched the exchange of coolant poor into the radiator and back into the engine again and it continued to do this while the engine overheated. They have spent so much time with it they all are scratching their head and have came to the conclusion it must be overbored or internal heat damage. They told me the price of rebuilding my engine is not worth the squeeze and to just buy a used 302 rebuilt engine ($2100 engine + $1500 labor + $200 new water pump (might as well) + $300 miscellaneous gaskets/fluids = $4100). OUCH!

Thoughts? Ideas? Questions? Concerns? Feedback?
 
#14 ·
As just about everybody else has suggested, the first step is to find a new mechanic. Water can not pass "too fast" through the radiator, and if friction was causing the excessive heat something would have seized already.

What is the temperature when it is "overheating", how fast does it take to reach that point and does it overheat both at idle and going down the road?
 
#15 ·
What fan are you running?
Do you have a shroud?

If your block is 60 overbore it is scrap if it needs to be rebuilt.

Rotted cooling chambers don't cool well, especially with a 60 overbore. That scale is the iron rotted away in the cooling system giving the walls a rough surface for the water to flow through/heat to transfer/etc.
 
#16 · (Edited)
The OP says seasoned vintage Mustang mechanics.... Really strange...anyone hear of this place? Alamo Classic Ponies...maybe sells Mustangs? Very strange!
Googled says they specialize in vintage Mustang repair/rejuvenation.
 
#21 ·
Alamo Classic Ponies. They do it all if it is vintage Mustangs. Why is that strange? They don't sell Mustangs, they fix and repair everything engine/suspension/transmission/body/paint/interior.

The have a large selection of original mustang parts also.
 
#18 ·
From the FlowKooler website. You might want print it out and send it to the mechanic that will no longer be giving you advice. :


Z

Hi Flow Water Pumps that end overheating, Quality Jeep radiators and off road custom radiators for J | FlowKooler Hi Flow Water Pumps



Hold on...doesn't the coolant have to have more time in the radiator to cool?

No. But a lot of people still think so. We have come up with some explanations for the Doubting Thomas.
Debunking the I Can Have It Both Ways Theory
The water has to have time to cool argument is most common one we hear. In a closed loop system if you keep the fluid in the heat exchanger you are simultaneously keeping it in the block longer. Unfortunately, the block is the part that is generating the heat. Sending hot coolant from your source (engine) through the heat exchanger (radiator) to the sink (air) will transfer heat as long as there is a temperature difference between the source and sink. The engine is still generating heat the whole time so why keep the coolant there any longer than you have to.

Debunking The Conscientious Electron Theory
We hear that the coolant has to stay in the system longer to cool but what is heat transfer really but conduction, convection and radiation of electrons. The fluid in your system transfers those electrons based principally on the source-sink differential and the exchange material's transfer rate. An electron moves at varying speeds - Bohr's model has it moving at 2 million meter/second. But let's just agree it is fast (really really fast). Far faster than the flow rate of the water pump. Your engine coolant's electrons do not know (or care) how fast you send then through the system - they just knows that the source is hotter than the sink and off they go.

Debunking Grandpa's Flathead Theory
"But wait a minute, I know Grandpa' used to put washers in his flathead to slow the flow and cool his engine." We know people did this too. They still do it but the cooling benefit is not from the slower flow but the pressure that builds from the restriction. Consider that Grandpa had two flathead water pumps sending twice the volume through the same size radiator core. Ask him and he might tell you his overheating woes were really as he tore up the track at high speed. Grandpa caused cavitation in his pump by with higher rpm and unrestricted flow and the result was overheating due to cavitation.

Restricting his flow with a washer build up his pump pressure and pressure in the block helped reduce the onset of hot spots on his cylinder walls and formation of steam pockets. So Grandpa was on to something but just not for the reason most people think. This restrictions makes sense when your rpm is excessive but it rarely makes sense normal driving conditions.

If you doubt this thinking then try this simple Ask Dr. Science experiment where you restrict the pump on the suction side; just clamp off the lower hose while you watch your temp gauge. Hopefully, you will debunk Grandpa's theory yourself before you experience vapor lock.

Restriction is not all bad if it serves to prevent cavitation. Cavitation occurs when a pump turns so fast that you generate lower pressure and air bubbles or vapor forms. These bubbles eventually implode and damage the engine block wall and impeller. Rapidly spinning the impeller can literally rip the air from water but may not actually move the fluid, it's tantamount to turning an eggbeater in a paint bucket. Restricting the fluid flow to raise system pressure in the block may help prevent cavitation at higher RPM but is it necessary for most vehicles?
No. Most vehicles do not need to restrict flow because they do not reach or sustain high RPM. Additionally, thin aluminum radiators already restrict by design e.g. fewer rows of tubes. Restrict it further and you may as well hose clamp the lower radiator hose and we know how that works out. When you face Grandpa on the track you may want your washers, otherwise, keep them in the toolkit.

Simply put, you have a far better chance of keeping your cool with a greater flow rate through your heat exchanger than gathering heat in your engine block.
 
#19 ·
From the FlowKooler website.

Debunking Grandpa's Flathead Theory
"But wait a minute, I know Grandpa' used to put washers in his flathead to slow the flow and cool his engine." We know people did this too. They still do it but the cooling benefit is not from the slower flow but the pressure that builds from the restriction. Consider that Grandpa had two flathead water pumps sending twice the volume through the same size radiator core. Ask him and he might tell you his overheating woes were really as he tore up the track at high speed. Grandpa caused cavitation in his pump by with higher rpm and unrestricted flow and the result was overheating due to cavitation.

Restricting his flow with a washer build up his pump pressure and pressure in the block helped reduce the onset of hot spots on his cylinder walls and formation of steam pockets. So Grandpa was on to something but just not for the reason most people think. This restrictions makes sense when your rpm is excessive but it rarely makes sense normal driving conditions.

If you doubt this thinking then try this simple Ask Dr. Science experiment where you restrict the pump on the suction side; just clamp off the lower hose while you watch your temp gauge. Hopefully, you will debunk Grandpa's theory yourself before you experience vapor lock.
Ha! That is funny.
The biggest problem with the flathead is the pressure the pumps are able to create in the system.
There are no "backs" behind the impellers, they merely sit in a huge cavity in the block.

The OP's real issue is his current "mechanic" as others have already astutely pointed out.
 
#36 ·
There is a lot of variation in regard to overboring being the cause of overheating. In light of that, ones own personal experience can't be extrapolated to indicate what's to be expected of someone else's engine. But as a very general rule, the Ford straight 6 is more tolerant of overboring than the 289 or 302 V-8's. Some people can get away with a 0.060" overbore on a V-8 without the engine missing a beat. But there are numerous documented cases of just a 0.030" overbore resulting in overheating issues on a SBF V-8. That why I routinely just go to 0.020" if the block will clean up, and they usually do.

Z
 
#26 · (Edited)
They have determined it is not the fault of the cooling system but instead discovered my engine is producing to much friction causing the thermostat to remain in the open position allowing water to constantly flow from the engine to the radiator and back into the engine again before the fluid has had an opportunity to cool down in the radiator.
This sounds like complete BS to me. They don't have a clue. "Internal friction"? That wouldn't overheat, it would just seize.

Now, your mention that it may have an .060 overbore would have some weight, except you report that it ran without overheating before certain repairs.

You have not taken it to anyone competent yet. Replacing upper and lower hoses to cure overheating? I knew better than that when I was 16 (when the dinosaurs walked). Heck, the backward thermostat proves they are incompetent. New fan shroud? Was there an old one? The new shroud melted? If so, it's a total piece of crap and makes anything else they did suspect, too. Then they put in a flex fan? I would only install one of those at the point of a gun.

And how was this circus watching "the exchange of coolant poor into the radiator and back into the engine again and it continued to do this while the engine overheated."? With the cap off there's no way it wouldn't overheat. What heat rating is your thermostat? Should be 190°F. Anything else is not factory spec.

The OEM fan shroud for 65-66 was steel, which melts at 2500°F. Get one.

You have a shroud, yet they thought moving the fan closer to the radiator would help. Sheesh.

I'd be using a steel clutch fan with thermostatic clutch. OEM 7 blade, but if you can't find one, an aftermarket 6-blade will do.

And have the distributor advance curves adjusted. I've seen a 2° error cause overheating.
 
#28 · (Edited)
Incorrect rotation water pump or cooling system blockage? If you take the radiator cap off and rev the engine, can you see the coolant flowing? Did you check for head gasket tabs to ensure they're not on backwards? What's the IR temp of the intake near the thermostat after a drive? Was the thermostat tested by placing it some boiling water and checking if it properly opens?

BTW- If your car got hot enough to warp steel sheet metal (~900 deg F) then many other items would have been damaged.
 
#29 ·
One idea that has not yet surfaced is that you might have a slight head gasket leak and combustion gases are seeping into the cooling system and superheating your coolant. There are testing devices (Tool rental program at O'Reilly's plus a bottle of testing liquid) that allow you to chemically determine if combustion byproducts are circulating in your cooling system. Your investment in this diagnostic procedure is around $10.00 for the testing liquid. Though a PITA, changing out head gaskets is less expensive than a new engine.
 
#30 ·
You said. "While there I replaced the old R12 A/C and replaced with new R134A A/C. Did oil change, tranny flush, radiator flush and put the car into my trailer" And You drove it with no problem before the AC work and fluid replacement, the problem should be related to the work that was done. Did you do the work? Was the water pump replaced? I would look very closely at the water pump.
 
#38 ·
My brother did the work, he is a certified mechanic in Boise and he said he did not touch the water pump.
 
#31 ·
Tough story - nix the mechanic, he is working on a downpayment for his next yacht which he will no doubt name "Pony Trick".

I only have long shots for you, beyond what has been stated. First thing i would try is removing the ac belt. Its the only thing you changed between it running fine and it overheating. Told you it was a long shot but its an easy one.

Second perhaps your harmonic balancer slipped and they do slip. Need to insure tdc is really tdc.

I would take a thermal temp gun ($30 at sears) and see if you can find areas in the motor that are hotter than other areas e.g. One bank or around one cylinder... as it warms up. Don't let it saturate with heat first.
 
#34 ·
Heck even changing to a 4 row radiator is cheaper than a rebuild. I would never get an aluminum radiator anyway...Heat transfer is not as good as an OEM. I went to a 3 row and a shroud on my 67 and have never looked back.
 
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