427 S.O. Overheating Questions

[elmariachi]

I have been helping a buddy try and diagnose his overheating side oiler and so as a last resort, I thought I'd start another seasonal overheating discussion. I've tried to provide as many details as possibleso PLEASE READ THIS BEFORE YOU POST and ask me if the __________ has been checked or changed:

This engine is a 12k mile medium riser, 500HP, Edelbrock heads, Cometic head gaskets, MR intake, 850 Holley DP, 9.5:1 compression, solid lifters, typical setup with external Mocal oil cooler. Car would show idle temps of 180F, NEVER ever exceeding 190F on the hottest days and down-the-road-temps at 165-180 depending on ambient temps. Never in 12k miles has it showed any signs of heat buildup or overheating. Then the bypass hose blew. The car overheated to 240-250F before he could get it shut down and off the road. Bypass hose was replaced, refilled and burped and ever since, idle and low speed temps rise slowly past 180 and on up above 200 and the car either has to be shut down or run above 80 down the road to cool it off. With a blown head gasket looming, we have worked to eliminate the easier/cheaper stuff first:

Step 1: Check temp gauge. Using IR gun confirmed temp gauge is working.

Step 2: Check for signs of blown head gasket. Oil is clean, plugs all clean and showed no issues but replaced anyway. No moisture or smoke in exhaust pipes. Ran chemical test on coolant TWICE, no signs of combustion gas in cooling system. Also checked cylinder head temps with IR gun and all of them are close to one another 250-300 while engine is at 185-200.

Step 3: Compression test (not a leakdown). All cylinders were 140-150 psi. A little lower than you'd like but all relatvely close.

Step 4: Ensure no air pockets trapped in cooling system. Had the system pressure tested by reputable and knowledgeable Superformance dealer. Test revealed leaks in radiator (car is 15 years old) so a NEW Fluidyne Cobra radiator was installed so system could be pressurized and tested (so much for cheaper stuff first.) Problem persisted after test/evac so a BIG single puller fan and two pusher fans were installed. No resolution. Replaced the water pump, radiator cap, all hoses and 180F t-stat. Radiator surface temps show 140 at the middle and bottom of the radiator while the IR gun aimed at the temp sender and dash both shows 200-210F. Fans and radiator are apparently doing a great job yielding a 40+ degree differential. On a related note, water level is constant in the expansion tank (no bubbles, leaks or overflow), but both water pumps show an unimpressive amount of flow at idle through the tank. System is running distilled water and water wetter, as it always has.

Step 5. Check base timing. Possibly the distributor was somehow bumped and idle timing retarded during adjacent plumbing repairs. Checked base timing, 18* with 36 total, no issues.

The radiator seems to be doing a great job of dissipating the heat from the coolant, but circulation is still suspect with both water pumps (once of which is a fresh rebuild.) Once the car heats to 200-210, you can shut it off, let the fans run for 2 minutes and then start it, and the engine instantly draws in the cool water from the radiator and the temp gauge plunges to 170-180. But over the course of the next 5 minutes it builds back up to 200+. All of this even with a 3' diameter shop fan running on high jammed against the nose.

Before you post, keep in mind that all of this started when the bypass hose blew. So its not pulley drive ratios or the like because that has not changed. If its a blown or leaking head gasket, could we be getting enough combustion gasses to heat the adjacent water this much but not enough to show up in either the chemical test, compression test, on the plugs or out the exhaust?

Thanks in advance.

Jim

[sharkx]

I would guess that the lower radiator hose is damaged internally and is collapsing. As soon as you shut off the engine, internal pressure reinflates the hose and then it's good for a few minutes.

Sharkx

[elmariachi]

Originally Posted by sharkx

I would guess that the lower radiator hose is damaged internally and is collapsing. As soon as you shut off the engine, internal pressure reinflates the hose and then it's good for a few minutes.

Sharkx

Its brand new, doesn't have a restrictive bend, has the spring reinforcement inside, and does not change diameter during the shut-off/restart process.

[Jerry Clayton]

what do you mean by two water pumps?

what do you mean by BIG puller single fan???

Does it have underdrive pulleys on it???

By running at 80mph down the road you are doing three things---
1--speeding up the water pump and thus coolant flow
2--forcing more air thru the radiator
3--generating more voltage which will then run the fans better

[elmariachi]

Originally Posted by Jerry Clayton

what do you mean by two water pumps?

The original 12k mile Edelbrock and a freshly rebuilt Ford cast. Tenps are exactly the same with both.

Originally Posted by Jerry Clayton

Does it have underdrive pulleys on it???

20" 3000 cfm, same that was on it before. Pulleys are stock diameters.

Originally Posted by Jerry Clayton

By running at 80mph down the road you are doing three things---1--speeding up the water pump and thus coolant flow
2--forcing more air thru the radiator3--generating more voltage which will then run the fans better

But even at that, it will not run at the 160-175 it ran out down the road before the bypass hose failure.

[Excaliber]

Man that setup sounds a LOT like mine!!! Solid lifters and the whole ball of wax. I chased overheating issues like you for a long time, never "that bad" but on a hot day always threatening to overheat and running hotter than I liked.

Eventually I too changed water pumps, from the old Ford OEM iron to a new Edelbrock. Whoa, that made a big difference right away. Apparently the OEM style pumps came in two formats, high flow and normal flow. Apparently the newer alloy type pumps are ALL high flow. So, one could assume an OEM Ford pump would work fine IF it was the high flow version, but I have no idea how to tell one from the other.

Anyway, if you have a modern alloy pump already, keep looking for the problem...

Sometime back I blew a hose and lost water and the engine got hot, how hot I don't know, the gauge doesn't read right when your OUT of water!! Anyway, got that fixed, everything seemed to be back to normal for awhile. Then I noticed it was starting to run hot, hotter than normal, before long TO dam hot!! Tried pressure testing the radiator, it held pressure good, didn't leak down at all. Looked for signs of water in the oil, nothing. Excess water out the tail pipes or white smoke, nope, nothing there. Dam, a real head scratcher. Plugs looked clean all around, compression good. Kept driving it, didn't know what to do, eventually determined than one plug was really really clean and nice compared to the others. Whats up with that? Looked closer, found some traces of water in that cylinder!!!!! A very slight blown head gasket, pushing compression into the water jacket, over pressurizing the radiator system, blowing water out the overflow. BUT, it would only do that when I drove it HARD. Driving normal, it would be OK a long time, get on it hard ONCE, and the temp would climb and it would be hell getting it back down to a good temp. Keep driving it hard and it would eventually blow out enough water it would STAY hot, never would come down.

The freakin' head gasket leak was so small I had to confirm it with a magnifying glass! I couldn't believe my eyes. Anyway, runs great ever since that, go figure...

[patrickt]

ElM... did I read that you had the oil checked for even a drop of coolant?

[elmariachi]

Originally Posted by Excaliber

Anyway, if you have a modern alloy pump already, keep looking for the problem... The freakin' head gasket leak was so small I had to confirm it with a magnifying glass! I couldn't believe my eyes. Anyway, runs great ever since that, go figure...

Car had an aluminum Edelbrock on it for 12k miles up until the bypass failure, and we have tested both that Edelbrock and a newly restored Ford water pump and the results are identical.

Originally Posted by patrickt

ElM... did I read that you had the oil checked for even a drop of coolant?

No, an oil sample has not been sent out to the lab but that was on the short list of "last ditch items" for this week.

[patrickt]

OK. One of my old oil reports is in my gallery. In the "antifreeze" section of it the reading is zero. Obviously, anything other than zero bird dogs the problem.

[Excaliber]

Just musing on this problem, may not be applicable...

In my case I determined that the VERY clean plug was a result of water in the combustion chamber, that has a tendancy to cut carbon and clean the chamber in general. I found what I thought was a bit of moisture as I cranked the engine over and felt, sniffed, inspected the compression gases being pushed out the empty spark plug hole, which led to the conclusion, blown head gasket.

Of course I changed the oil, but I've always wondered, is it possible that compression gases were going into the water jacket when I was driving "hard" but that no water was actually getting into the oil? Perhaps a small amount in the combustion chamber, not enough to really show itself, other than a "hunch" and a super clean plug.

Perhaps a blown head gasket doesn't always mean water in the oil? Is the question.

[cobred]

Here is a freebe to try. Drive it to get the engine to the too hot point and shut it off in the garage so you can work on it. Let it sit overnight. In the morning disable the ign. so it doesnt start and crank it over a dozen or so revolutions and then pull the plugs and see if any plugs are wet with coolant. Its worth a try.

[FOMOCONUT]

Are you getting any coolant pushed out the top of the radiator ? Jerry

[RICK LAKE]

Elmariachi Jim it sound like a leaking head gasket If the motor was overheated 1 time it is possible there is a spot for compression to leak into the coolant system. You don't always get alot of bubbles. This is the problem with aluminum heads and iron blocks.
The other thing is the water pump, Edel has 2 different ones. One is a high flow one that comes with a plate on the fins of the impeller inside the housing the other one doesn't. If you are careful, you can pull the back cover off the pump and see which one you have. DON'T rip the geasket.
I know there has been a couple of threads about AUX fans in the front of the radiator and how much flow they help or slow down. ERA sell there cars with a deflector and only 1 good fan. Alot of guys are having no problems with over heating.
The simplest thing to do is get a good pressure tester with a long hose and install it on the rad fill neck and go for a ride down the road. See how much pressure builds up in the system. This is an old trick that some guys used on there motors for racing. They know when the motor is about to toast with higher pressures. Simple and works if you have a base to start with. I think you have a pin hole and the motor seals it when cold and when hot cooks. A would also have the heads checked for straightness if you end up going my way. HEY just had a thought, Check the system out and put some DEX in the coolant system and see if the high temps stops???? Mom pasted last night, later. Rick L.

[vector1]

i think you have a small leak into the coolant somewhere, building pressure which blew the bypass hose and torched the old radiator.

i would do another cooling system pressure check and leave it on a while to see if it is dropping even the least little bit, then i would do a leakdown on all the cylinders with a leakdown gauge.

from there you know you have a good system and can look at other possibilities if nothing comes up.

in addition, if you had a steam pocket leave the engine which is coolant coming in contact with a hot cylinder and enter the radiator it will tear up a radiator pretty quick.

[Bill Bess]

Dump a tube of Alumi seal in the thing and see what happens, the stuff works wonders. If no improvement, go for the head gaskets and water pump replacement.
Heck my FE gets up to 210 all the time in hot weather in slow traffic and at signals, but cools right down as soon as I get moving.

[Clois Harlan]

Bill is right, the Aluminium Seal works wonders and I have used it while at a race and it sealed like a champ. My guess is a minute leak in your head gasket too. Follow the instructions on the sealer to the letter and you wont' be sorry.

Head gasket can be replace this fall or winter. The sealer will not harm your engine just in case you were wondering.

Clois

[elmariachi]

Originally Posted by cobred

disable the ign. so it doesnt start and crank it over a dozen or so revolutions and then pull the plugs and see if any plugs are wet with coolant.

We have checked the plugs on cold start with no noticeable issue, but I suppose we can try this easy enough.

Originally Posted by FOMOCONUT

Are you getting any coolant pushed out the top of the radiator ? Jerry

None.

Originally Posted by RICK LAKE

Elmariachi Jim it sound like a leaking head gasket Mom pasted last night, later. Rick L.

Rick, you have a PM.

Originally Posted by vector1

i think you have a small leak into the coolant somewhere, building pressure which blew the bypass hose and torched the old radiator.

The old radiator was fine, it just had a couple of leaks that were too tough to repair, and it was probably time for a new one anyway. But I suspect you may be right, a very small compression leak that isn't showing up anywhere but still escalating water temps.

Originally Posted by Bill Bess

Dump a tube of Alumi seal in the thing

That's certainly worth a try. I'll report back on this stuff later in the week when we have time to wrench a bit more.

Any other suggestions post 'em up.

Thanks guys.

[Excaliber]

Dang, I wish I had tried that Alumaseal trick before I took the head off. Well NOW you tell me!!!

[patrickt]

Originally Posted by Excaliber

Dang, I wish I had tried that Alumaseal trick before I took the head off. Well NOW you tell me!!!

I successfully used Bar's Leak on a GM intake/head area leak earlier this year.

[priobe]

Hey Rick,

I only see that Edelbrock only make 1 style water pump with different finishes, reflecting different part numbers

For 1970-92 429/460 (3/4" pilot shaft) 8866 8876 N/A
* Left-hand inlet, includes new backing plate. Fits all 1970-92 429/460 V8s in passenger cars, trucks, vans and motorhomes. Has heavy-duty 3/4" ball/roller bearing. Dimension from block surface to hub: 5-1/2". Inlet diameter: 1.98".

FORD FE - Standard Rotation


I would lean more toward a blown gasket