• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR6 Overheating Tr-6

Share this page

B

Brokermd

Freshman Member
Offline
Hi,
I have a 72' Tr-6 I just installed a new cam, 150hp english cam, rebuilt carburators, head work, ss valves,springs.... Increased compression to about 9.5, added falcon exhaust,k/n filters. I have carfully tuned the carburators to make sure they are not too lean. On start up the car overheated, I changed the thermostart to a 160 deg and a temperature sender. The temperature reading on the guage after a 10 minute drive went up to about 3/4 hot, and it continues to rise in stoped traffic. I just flushed the radiator and added waterwetter and it showed a little improvement but it is still showing hot on the guage. I have not yet measured the temperature with a ir thermometer, nor checked the coolent temp. But the engine comartment feels very hot after a drive. I am getting kind of upset hat after all this work this is happening.

What do you guys suggest i do next?

Mike
 
Mike: Meaning no disrespect, but have you tightened the fan belt enough? Actually fan belt is a misnomer, as the fan is driven by the crankshaft, it is actually more of a water pump belt. I replaced my water pump and fan recently only to have similar symptoms as you report, but not quite as bad. I thought I had tightened the belt properly, but it wasnt. It did not squeal, but had definite slack. When I re-tightened it by the book my problem went away, and now the gauge will creep to the right of N only after sitting in traffic, like it did before.
The other cause that comes to mind is maybe the new valves are binding in the new guides after they warm up a bit, which will generate some heat to be sure.
 
Mike,

I had similar overheating problems on my 70 TR-6. When I started my restoration, the first thing I did after engine disassembly was to have the block tanked. The water passages were full of junk, and after the rebuild, the car won't get past the midpoint on the temp gauge, even sitting in traffic on an 85 degree day. Hopefully your problem is something simpler, since you already have the engine back in the car. Good luck...

Mark
1970 TR-6
 
Hi Mike,

You've done several performance modifications that will add to engine heat output. Whenever an engine is tuned for more horsepower, a by-product is more heat.

For example, the higher compression adds to engine heat. You mention a Falcon exhaust, but didn't say if that included headers. If so, headers add *a lot* of radiant heat under the hood. (If they are stainless steel, they can be wrapped to help reduce this. If mild steel, have them ceramic coated.)

Any time an engine is more highly tuned, it's likely to need more attention to cooling. A "summer" thermostat actually does nothing to improve the situation at normal operating temps, it simply opens sooner.

Some things you can do to help with cooling... some are easily done, others are more involved:

- Check the gauge and sender are giving accurate info.
- Check carbs (as you have done) *and* valve lash *and* ignition timing/advance for accuracy.
- Run colder spark plugs.
- Insure the water pump and all are working correctly and that no hoses are old, possibly collapsing.
- Put in fresh coolant, 75% distilled water, 25% anti-freeze. Add Water Wetter (as you have already done).
- Check the radiator for any sort of air blockage, bent fins, etc.
- Make sure there is no air trapped in the cooling system.
- Be sure the radiator shroud is in place, very critical on all these TRs.
- Keep paint on the radiator to a minimum. There are special radiator paints that should be used, give coverage with minimal thickness.
- Flush the radiator (as you have done) with a coolant system flush/cleaner, carefully repeat if needed and watch that all water coming out of the system is clear, no debris. Follow the instructions on the flushing/cleaning agent.
- As mentioned by Mark, during engine rebuild it's ideal to tank the engine and clean it out very thoroughly, to insure full flow of coolant through all the internal passages.
- Avoid mounting anything in front of the grill, such as driving lights.
- Have the radiator "cored", this is a cleaning process to insure it's not got a lot of buildup inside, sort of the next step if flushing isn't sufficient.
- Upgrade the water pump (www.britishframeand engine.com)
- Check that you are using the right type of thermostat (the 4 cylinder TRs use a "sleeved" thermostat, very important to effective cooling of those engines, but I'm not sure if the 6-cylinder cars also require a special thermostat)
- Give the air entering the engine compartment a means of exit, such as fender vents.
- Upgrade the fan: change to a thermostatically controlled electric or install a higher volume mechanical fan.
- Install an oil cooler, preferably with a thermostat control to keep from over-cooling the oil and to prevent heavy, cold oil at start-up from possibly over-pressurizing the cooler and its hoses.
- Install an aluminum radiator. This reduces weight, but also aluminum transfers heat better. Be careful to use the correct anti-freeze, though most on the market today are aluminum-safe. Aluminum radiators are pretty expensive.
- Wrap stainless steel headers.
- Ceramic coat mild steel headers or cast exhaust manifolds.
- Add a front air dam to the car to direct more air into the engine compartment and through the radiator.

I'm probably forgetting a few things, but maybe others will jump in with some additional idead. Hope this helps.

Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
 
Alan,

Who sells aluminum radiators for TR6s? I've been looking for one and haven't been able to find one. Thanks.
 
Mr. P.,
You will pay through the nose for an aluminum radiator. I took my standard TR6 radiator and had them rebuild it to a four core in lieu of the stock three core. There is plenty of room inside the frame for this change and it was quite cost efficient. I think the radiator shop charged me $164.00. Subtract the cost of overhauling your existing radiator by coring it and the cost then is really cheap. Fred's Radiator Shop in New Iberia, La. did the job for me. They specialize in large industrial oilfield radiators and are very expert in what they do. Thus, my thinking is to find a good professional shop in your area and the cost should be close. I chose not to coat the fins and left them a natural copper color.

Bill
 
[ QUOTE ]
Alan,

Who sells aluminum radiators for TR6s? I've been looking for one and haven't been able to find one. Thanks.

[/ QUOTE ]

Hi,

Yes, an aluminum radiator will be more expensive, but cools better and is lighter in weight, as a bonus.

Ken at www.britishframeandengine.com might know where to get one for a TR6.

https://www.tonydrews.com/Jack_Parts.htm offers one for TR4, says something about offering a TR6 rad, too. Sounds like a custom made item.

Griffinrad.com will make a radiator to your specifications.

I've heard of folks using one of the BeCool universal application radiators. Available at www.summitracing.com part BCI-65005

Some or any of these might require fabricating brackets, rerouting hoses or custom made shrouds.

In England, RevingtonTR offers an "ally" radiator for TR6

Hope this helps!

Alan Myers
San Jose, Calif.
'62 TR4 CT17602L
 
Back
Top