Overheating and stumped?!!

[mustangsilly]

I've had the 200 back on the road since last spring and it runs great. I did CI headers, cam, weber 5200 and Pertronix, milled head.060, decked block .015.
The darn thing overheats after about 15 minutes driving or idling. I removed the AC condenser to get full air to the rad, flushed the rad, even took out the thermostat and put in a new water pump. Tried timing anywhere from 6 deg BTDC to 12 deg. BTDC. Nothing makes a differrence. Pulled the head to make sure the gasket was on right. Fan belts are all tight, heater core flows easily. Used an infrared thermo just to make sure the gauge wasn't off, but the top tank is over 200 deg. It also smells hot! The only other thing i can think to do is jet richer, but the plugs are right where they should be in color. Hate to go richer unless that's the only alternative. Anybody got any ideas?

 

[CZLN6]

Howdy:

Have you checked you lower radiator hose for cavitation and or collapse? Just a thought. You didn't mention your hoses.

Adios, David

 

[JackFish]

Just wondering if it's boiling over?
What pressure rad cap are you using?

 

[Canary94GT]

Also, what kind of coolant are you using?

Green? 50% water, 50% coolant or 30% water and 70% coolant?

 

[The Plankster Prankster]

what happens if you run it with the rad cap removed? any bubbling? anything else abnormal?

also, you should check your oil to see if any coolant is leaking to there. i've heard of blocks or heads having cracks to leak water internally as such, as you have already verified it wasn't the head gasket itself

 

[JT81stang]

You mentioned that you removed the thermostat - did you put another back in? If not, then there's nothing stopping the water from circulating long enough for the rad to cool it. You need to run a thermostat, whether it's a 160* or 180*

 

[jahearne]

Are you running the stock radiator? It may not be able to keep up with your new modified engine.

 

[69.5Mav]

A copple of things to check.

Is your coolant flow blocked. Remove the thermostat (allows you to see coolant flow with out waiting for the engine to warm up so you can more easily work on it if need be) and watch the coolant through the radiator cap hole. It should show a strong flow like a rushing river.

If not you could have a blockage in the engine, a blocked radiator or a colapsing hose.

If you do have good flow then you might have a radiator that the fins have come loose on ( how old is your radiator). It will look okay but will not dump heat very well, use your infar red thermometer to read the top tank and bottom tank temperature, they should be thirty to fourty degrees differrent.

You could be running to retarded. Find top dead center and check your timing mark.

You could be running to lean.

You could have a combination of all of the above which individualy won't make you over heat but together give you problems.

You should be able to idle all day with out over heating even with a modified engine. At idle the engine is producing very little power and heat.

At higher power levels you may very well need a better cooling system but not at idle.

 

[wallaka]

You mentioned that you removed the thermostat - did you put another back in? If not, then there's nothing stopping the water from circulating long enough for the rad to cool it. You need to run a thermostat, whether it's a 160* or 180*

This is a myth. Faster flow equals faster heat transfer, period. All a thermostat does is help the engine warm up faster.

How hot is the actual temperature? Is it boiling over? I wouldn't be concerned with anything under 215 degrees, personally. It should definitely be at least 190-200 degrees.

In my experience, all engines with a mechanical fan will run hotter at idle than when cruising. The reason being reduced airflow through the radiator as well as the water pump pumping less.

Did you paint the engine? I noticed that on mine, there was a "hot" smell until the paint cured. Not meaning to be obvious, but it is easy to overlook.

 

[ponyrider200]

It normally takes about 15 mins for an engine to warm up, give or take ambient air temp and other variables. If you are overheating in that amount of time, it seems logical, that something is blocking flow to or from the radiator. You said you changed the T stat, is it possible it is in back wards? You said the 200 is back on the road after engine work. When you did the head work and changed the head gasket, did the gasket get put in backwards and block ccolant flow thru the head?

 

[jamyers]

...How hot is the actual temperature? Is it boiling over? I wouldn't be concerned with anything under 215 degrees, personally. It should definitely be at least 190-200 degrees.
...

I'm with Wallaka, how hot is it getting? 200 degrees at the top tank after idling isn't anything to worry about, unless you've got a really low-temp t-stat in there, like a 140 or 160.

 

[MustangSix]

The #1 cause of overheating that I've encountered is crap in the radiator. Every one of these engines is full of rust, sand and flakes. Every one. Even the ones taht came back from the shop all shiny and clean on the outside had to have the passages cleaned. It has to be cleaned out or the damn stuff will clog the radiator in short order.

The #2 thing I've found that causes overheating is a failed load-o-matic distributor vacuum system. It has to work or the car will overheat while cruising. The engine never gets more than initial timing and under load that's not enough.

 

[MPGmustang]

I've been having overheating issues too and want to look into aluminum rad's, i've found this article helpful

http://www.carcraft.com/techarticles/cc ... index.html

the aluminum radiators i think from experience work best when it has at least one 1inch tube, so if your looking for a new rad, go for this option as it does make a difference... but other than that the copper/brass is supposidly better cooling...

MustangSix- how do u know your LOM distributor is bad? is is possible to run better with one that is only cintrifical advanced?

*Edit- i don't want to hi-jack so if you have answers you can post them on my thread here viewtopic.php?f=1&t=58715

 

[mustangsilly]

Thanks for all the suggestions... A couple of points to clarify

1) I pulled the head and checked the gasket alignment and it all checks out
2) I have run with and without a thermostat and it still runs hot.
3) The lower hose (which is new) is not collapsing
4) I put on a new 13 lb. rad cap AND a new water pump
5) The "hot smell" is still there after 5 months of heating and cooling, so all the paint should be cured
6) I changed to a 68 dizzy when I put on the Weber - no Load-Matic
7) The gauge, which never showed "HOT" before the engine mods, now pegs on the "H" side
8) The radiator was boiled out, but has not been replaced
9) With the radiator cap off, the flow is evident in the upper tank
10) No coolant in the oil and no sign of coolant loss
11) I'm running a 50/50 mix of AF (ethylene glycol) and H20)
12) I'm using a 5 blade 17" fan which came stock on the AC equipped engine, even though I've removed the AC completely including the condenser
13) When I pulled the head, I ran a garden hose through the heater inlet and I got water out of all of the passages
14) I've tried timing everywhere from 0 deg (it would hardly run) to 12 deg BTDC (where it runs great) but no change in temperature

This problem just has me totally baffled. What am I missing? More ideas???

 

[Canary94GT]

edit:nevermind

 

[jamyers]

Hmmm...

I'd recommend spending the $50 and getting a GOOD temp gauge that'll give you accurate, measured readings. Factory gauges are notoriously unreliable, especially the 40-year-old ones. I've seen Ford and GM gauges that would seemingly range all over the place - and a lot of lower-priced (Eqqus, etc) temp gauges can be off by as much as 20 degrees. Then you'll be able to tell exactly how hot it's getting and when.

Once you know that, then it looks like the only thing left to do is replace the radiator - which is what I'll bet it's needing. I've had radiators boiled out at reputable shops, and it seems to be a 50/50 success rate. Something about an old radiator...either the fins come loose, tubes get blocked off due to dirt or the radiator shop cutting them out of circulation, or a number of other things. My latest experience with radiatorsis going from an old copper-brass 2-row that had been boiled out at least once,had 4 tubes capped off, and cooled "OK" but not great; to an all aluminum 2-row (1-inch tubes) that cools better than is probably needed (I likely could have gone with a 1-row aluminum and been fine).

A coolant filter (Gano, iirc) isn't a bad idea at all - as stated above, our old engines have a ton of gunk inside them.

 

[mustangsilly]

Thanks to all for taking the time to respond. Looks like a new radiator is the next thing to try. I don't know what else to try and it's about the only part in the cooling system I haven't replaced. I'll let you know if that solves the problem.

 

[Frankenstang]

Hmmm...

I'd recommend spending the $50 and getting a GOOD temp gauge that'll give you accurate, measured readings...Once you know that, then it looks like the only thing left to do is replace the radiator - which is what I'll bet it's needing.

+1 That would be the way I'm leaning based upon what you've already done. What's surprising (as I experienced the same thing when I changed to a new aluminum radiator...fleabay as well) is the improvement in cooling some seem to be experiencing going from copper to aluminum (I had similar results)...when copper is by far a better thermal conductor than aluminum (transfers heat better).

http://en.wikipedia.org/wiki/Thermal_conductivity
Lead 35.3
Aluminium 237 (pure)
120—180 (alloys)
Gold 318
Copper 401
Silver 429
Diamond 900 - 2320

Almost 2 to 1...although not quite as good as the stuff you can't afford to build a radiator out of

This leads me to believe that the new aluminum radiators probably have 1) some improvement in design (larger rows or some such) and 2) that the old copper ones being replaced are really on their last legs (as mine was) in order to see such a drastic improvement over copper which is better as disapating heat. I'd probably think it's more the latter with regard to the age of most of these old rads. Makes you wonder what a brand new copper would do

Of course aluminum also has the additional benefit of being cheaper (it's in all new car rads...that and plastic), also lighter, and lastly but not any less important IMHO is they don't corrode/oxidize in the same way over time. A closed system that's kept regularly treated with rust inhibitor aka coolant (the other purpose of anti-freeze) should not corrode excessivley fast but in similar conditions it's my understanding that copper will corrode faster or otherwise stated is going to have more waste product/corrosion material to potentially clog the system over the years especially with the help of the iron oxide being manufactured in the hollows of the head/block.
EDIT: basically what Jack was saying...overload of crud, crud, crud

The other thing I'd like to weigh in on...count me in the camp that does not believe changing thermostats is going to affect your engines running temp significantly. The engine running temp is what the engine running temp is. You can temporarily impact it by changing thermostats, but its only temporary. Say the engine is running/peaks at 210 on a hot day...when cooler water from the radiator is allowed to enter the engine or conversely warmer water from the engine is allowed to enter the radiator...the temp may fall...but only temporarily...then the engine is immediately trying to get back to the 210 it was running at (given ambient temperature stays the same). If it's a cooler day and the engine tops the temps at 200...then same thing...at whatever point the water enters the engine from rad or leaves the engine to go to the rad (ie fully circulates) the running temp is only impacted temporarily then the engine again wants to seek out its normal running temp (given capacity and efficiency of the cooling system combined with ambient temperature effects).

Seems there's a few good threads going today on overheating so thought I'd throw my $.02 in here...gotta like the theory talk ...but don't intend to trivialize your current concern mustangsilly...good luck with the new rad

 

[JackFish]

Other than the temperature guage, and the smell are there no other signs of overheating?
You said the car runs great. You have modified it quite a bit, and it doesn't surprise me that it would run hotter. But I've pegged my temp guage over long highway runs, the car ran great, and never boiled over. I run a 16lb cap.

The temp is also being measured at the back of the head, in the hottest area.

And with the coolant mix you're running you're probably good to 230° before boiling.

 

[MustangSix]

The one and two row aluminum rads have more tube surface area, making them more effective than the copper/brass version with more tubes.

But the stock radiator is more than adequate for most 200 engines. The same radiator core was used to cool the 289. Only the outlets were moved.