Triumph Sports Cars

I purchased this car for back roads & cruise nights. I've been having issues with it running hot, both at
55 mph plus & in traffic. The radiator is 1965 Mustang spec, with a 16" electric fan & 180 degree thermostat.
The exhaust is stock manifolds placed backwards, so they exit @ the front of the block.

I'm thinking tnat the problem may be air trapped under the hood/bonnet, since the inner fender panels are
uncut, and there is a 56 Tbird hood scoop over the air filter (needed for clearance.) Wher would be the best place to
cut the inner panels to vent the engine compartment? If needed, i can attempt to upload some photos.

I've pulled the hood off,and will see if that makes any difference in the next couple of days.

Thanks for any advice !

Doug, Sparks, NV



Edited 2 time(s). Last edit at 08/12/2015 06:29PM by Moderator.

What are the dimensions of the radiator? Also , what do you consider running hot? Are you 100% sure the system has no air in it?

Photos might be helpful!

Do you have some sort of shield to keep airflow from passing over or around the radiator rather than through the core? Mustang radiators are probably the most popular size/style on this website, and are often used with SPFs in MGBs on account of they fit nicely there. 16" is a common fan size. Do a quick check to make sure it's blowing the right direction. Above 55mph it probably doesn't need to be on, but blowing the wrong way might be worse than not blowing at all. While you're at it, consider the wiring. Small gauge cable or an old switch can slow fan speed down significantly.

It would be a pity to cut the inner wings and then find the problem remains. There are many mechanical things to check first.

All air passing trough the front openings must pass through the radiator. The radiator is a 65 Mustang radiator
with auto trans cooler. I am running a 180 degree fail-open thermostat.. on an 80 degree day, by the time I have driven a mile and a half, the temp gauge is reading 200 degrees. If I putt along @ 30-45 mph,
it will tend to stay there. anything over 50-55 , and it goes up to about 215 degrees. In stop & go traffic
( like on a "cruise night" ) it slowly climbs up to 225 or higher.

I have removed the hood and plan to test it today to see if the problem persists. I owned a 61 Healey 3000, with a built 289 & BW 4speed, back in the mid 70's The electric fan was on a switch so I could run it as needed . ( I used the hole for the overdrive switch ). As long as i could run above 35 mph, no problem - in traffic, once it hit 180,it was time to look for a water hose, because it would keep getting hotter if I couldn't get up to speed, evn with a 160 degree thermostat. I had a reputable shop rebuild the radiator, but the problem persisted.
All the heat from the headers and radiator was trapped in the engine compartment. ( Ceramic and other header coatings were unknown at that time. ) I finally resolved the issue by putting a HUGE oil cooler for a truck in front of the radiator, with the heater hoses running through it, which added both fin area and coolant capacity..... and then sold the car to finance my sidecer reacing...

The experiences with the Healey are what leads me to believe that getting hot air out from under the hood
may be the problem. The 56 Tbird scoop may also be packing air into the engine compartment at speed. I have tried popping the hood in traffic, but it doesn't seem to help much, and at speed, I would imagine the high pressure would force air into, rather tahn out of, the engine compartment.

I am also thinking that running the C4 with 3.69 gears may be generating excess heat from the trans, and putting it into the radiator.....

Thanks for any replies, food for thought, etc.
Doug

I'm not sure on the physical dimensions of your radiator but I can barely get my sprite up to cruising temps with a fan running. I don't have any hood vents, just a scoop that forces air in, probably not letting much out. I used to have a th400 in it and the rear gears are steep... Still never ran hot, that's why I question the size or a blockage, etc

Well, I took her out for a spin @ 97 degrees this afternoon. She quickly hit 195-200 degrees, but maintained that for about a 3-4 mile run @ about 30mph, with 3 slowdowns to 15mph for school zone crossings. After turning onto the 4 lane and accelerating to 45-50, she was running betwwen 200-205 degrees. A long stoplight, rapid acceleration to 45+ up a curvy hill, and she was up to about 210. Stopped @ the bank for about 5-6 minutes, showing 215-220 degrees. After a brief hard acceleration to merge with 55-60 mph traffic,
showing 225 degrees, where she stayed for about 6 miles @ 55mph. After a mile on the 2 lane @ average 40 mph, turned onto my street & pulled into driveway, still showing 225. Shut her down, left the fan running
for a couple of minutes while opening the garage. Started her up, let idle for a couple of minutes, temp back down to 215 degrees.

With trhe hood on, she would have been running hotter sooner, & 45 mph on the 4 lane would ahve been required to keep her below 225. My conclusion is that trapped air may be a contributing factor, but someting else may be amiss. Having the upper radiator hose inlet to the radiator directly above the lower outlet hose may be preventing the radiator from fully functioning ? I am going to attempt to attach a couple of photos i took just now.

here are those photos (resized for uploading)

Disconnected jottings...

A good running temp would be around 210-215, so, hmmm. There is a problem both running and sitting. And indeed the running problem is pretty severe given you've just been poodling around with the engine not even heat-soaked, let alone the whole engine bay heat-soaked. I wonder if it's ever worked? Now that the PO has got shot if it, I wonder if he would level with you?

The fan cowl looks to be so far away from the blades that I doubt it's doing much, otoh it's probably doing no harm.

That coil would be happier if it were upright and moved away from the hot oil filter.
The filter itself is not helping, the oil is hot and there it is at the top of the engine bay.

The oil also cools the engine; is there an oil temp gauge and an oil cooler? But we're talking here about a test run that scarcely warmed up the oil.

So where is the trans cooler? And is it one of those thin but wide setups that occludes a lot of the radiator?

What else is in front of the rad? Anything? Horns?

If you take off the rad grille, you may be able to shoot the rad with an infra-red thermometer and see the temp distribution. As you say, if it's not a cross-flow, that's not ideal. But even so... I wonder if it was new when the car was built, or out of a donor.

What poundage pressure cap is it running?

Perhaps it's just the pic, but the fan belt looks to be riding a bit high on the pump pulley. If you feel the belt, is there a ridge on the sides near the top?
I wonder if it's slipping. Though that would mainly manifest at speed.

Finally, silly question, I suppose you are confident of the water temp gauge?

Ivor

Is it possible the engine is running lean?

Air trapped in the cooling system?

Head gasket leak letting exhaust into the coolant?

All easy things to check for. Plenty of TR6's running around w/o trapped air problems so I'd be looking for other causes.

I chased a hot running condition in a car recently and in my case, lean or rich had no effect, (not saying it may not be a factor with you Doug).

There are good pointers in the above replies but a Google search can lead you to websites that give you logical steps to fixing the problem whether it's overheating stopped or moving. Often, the failure is a combination of factors.

Off the top here, I wouldn't be looking at cutting the inner panels to vent the engine compartment. This is a liquid cooled engine and there is plenty of space for the hot air to exit the engine compatment under the car.

My TR6 has the stock hood and inner panels and has no cooling issues:



I hate to say this but I'm suspicious of the radiatior and cooing fan size. You may not have to go this big but an upgrade might fix the problem:

Another tip, not sure if it'll help but ignition timing can have a big effect on cooling. Sometimes changing the advance or base timing can let the engine run cooler, especially if you are using a distributor set up for a smog motor, which could be anything after about 1970.

Jim

I'd check for trapped air and the radiator may have problems etc... I have had many problems like yours and most of the time it ends up being trapped air in the system... I've got a griffin cross flow... It's not big at all by standards but like I said in a previous post, it more than does the job. On a side note, I'm a sucker for the cheetah... I'd own one now if the kit wasn't more than twice what a cobra kit costs... Its a very sexy car and you never really see one.

I wonder if the engine was assembled with the head gaskets on wrong. Do a google search on the term Ford 302 overheating head gaskets and you'll find discussions about the problem.

See here
[www.carandclassic.co.uk]
I'm debating whether to charge over there and buy it... but life is getting in the way. Hmmm

Anyway, blow up the pcs and look at the third one, what's been done with the rear edge of the bonnet. Clever.

Ivor

I can't really ad much, but I would just point out that even in the post where you talked about your experience with the Healey, and where you concluded that the problem was trapped hot air - the solution was effectively a larger radiator (the oil cooler)! Do you know the radiator is in good shape? Maybe corroded? What about the water pump? I know you can buy a two-core aluminum mustang radiator with larger passages for around $200. Also, maybe try adding an inline filler to the high point of the top hose to allow air to escape. Maybe an expansion tank in the highest part of the engine bay?

Finally, there's a lot of difference in electric fans - does it seem like it's moving a lot of air? It looks like you might have enough room to run an engine driven fan, which would probably move more air.

Ryan -
Thanks for your input. Unfotunately, an engine driven fan is not an option, as it wouldn't allow me to run a hood. I'm going to check on using a hand held surface temp reader to see what's going on with the
radiator. If it is not working properly, I think I will probably have to order a good one. I was talking with a rep for DeWitt Radiators during Hot August Nights ( www.hotaugustnights.net ) , and he said they could build me a radiator to my specs, since they make all their own components - He was pretty certain they could build a 2 or 3 pass crossflow, set up for a remote filler tank. The only downside would be finding a location for a trans cooler..... They could build one in, but with a crossflow design, I'd have to modify the cooling lines anyway.... I'd rather not mount it in front of the radiator.
I had been toying with the idea of using a remote filler tank, as used on some Fords in the 50's and 60's, and mounting it above the passenger footwell.

The giant oil cooler on the Healey added at least 2 quarts to the coolant capacity, allong with all the extra fins. I had to mount it in front of the pusher fan. More room in the Healey than the TR6 !

The fan seems to be moving quite a bit of air, and is on whenever the ignition is on.

Thanks to all for your helping me figure this out- I really appreciate it !

Doug

Have you checked the ignition timing? Your car sounds exactly like mine. Warmed up quickly and while running was always one heart beat away from the electric fan turning on. On just an ordinary hot day it was obvious the cooling system was barely keeping up as the running temp was a few degress higher than the 'stat rating. Advanced timing and the problem went away.

Bill



Edited 1 time(s). Last edit at 08/18/2015 08:14AM by Orange Alpine.

I will check the timing, but I think I've found a major part of the problem. I drove it with an ambient temperature of about 85 degrees, mostly at 45-55 mph, parked and went into the bank , came out, started it up, and headed back the same route as the earlier run mentined above. This time she got up to abot 205, and after pulling into the driveway, I did a temp check. The thermostat housiing was showing 208, the top
surface of the tank was showing between 200 & 195 in various spots, and 175 near the outlet - but some of the tubes on the driver's side ( which is opposite both inlet & outlet ) while showing 185 near the top, about 1/2 way down suddenly dropped to readings in the 120 degree range... So I'm pretty sure the radiator has some clogged tubes. Also, after sitting overnight, it was easy to squeeze the top hose, so there may be some air trapped in the system as well.

At tthis point, I think I'll drain the system of coolant, refill with water, and run it for a couple of miles with
the Arm & Hammer Washing Soda in it, and then flush the system out. and replace the radiator with a new
one. No point in contaminating a new radiator with any crud that may be lurking in the engine block !

Doug

I don't see any vacuum advance on the dist. hooking up vacuum advance on my car made a big difference.
Big difference between electric fans and how much air they move, my Spal extreme 16" fan uses 40 amps.
Hope a new radiator is all you need. Good luck

Well how did you make out with overheating issue?