View Full Version : TR2/3/3A TR3 Running Hot

Mickey Richaud
03-12-2003, 05:10 PM
Hey folks -
I'm new to the group and looking forward to participating.
My TR3 runs hot - foams out the overflow - gauge
reads well over 190...Here are the vitals:
- Newly rebuilt (professionally)
- New radiator core (but with the crank hole)
- New "sleeved" 'stat from Moss (actually
helped a little over the standard one that was
in there)
- Fresh antifreeze
- Tried a 4lb. and a 7 lb. cap (little better
with the 7)
Any ideas? I'm planning on attending the show in New Orleans next week, and know I'll be stuck somewhere in traffic.

Mickey Richaud

03-12-2003, 05:33 PM

Make sure you don't have *too* much anti-freeze in the mix (more than 75% will make it run hot)

Is your fan "backwards"? (won't work as well if it is)

Is your timing retarded?

Is your lower hose collapsing. It's under suction...if it doesn't have a spring inside it, or it's old, it will collapse and prevent flow. Warm up engine and rev up while observing...see if it flattens out.

I've seen some old water pumps with the vanes worn off after years of use....weren't leaking, but weren't pumping either.

Mickey Richaud
03-12-2003, 05:58 PM
Hadn't considered the antifreeze mix. May be a little more syrup than water. Will check on that.

Timing is fine - and, if anything, it's running just a little rich, so that's out.

Will check the lower hose, though it is new and should be fine. And I'm pretty sure it's a new water pump (at least, I think that's what I paid for!)

Thanks for the quick reply.


spit6 guy
03-12-2003, 06:10 PM
heres one see if the rear brakes are bindig if so the car will run hot . the rear have to turn free not be tight like american cars . I have had this problem

03-12-2003, 06:18 PM
Sounds like the thermostat. I have had new thermostats not work more times than I care to remember.

03-13-2003, 03:42 AM
hi there i dont have any solutions for you .. cause mine doesn't have an engine jet, but i did want to say ... "welcome".

also let us know what the solution to your problem was ... i'm affraid i will need it in a near future. graemlins/cheers.gif regards ... paul

03-13-2003, 07:04 AM
Hi and welcome to the Forum.

I'm afraidI don't know a great deal about TR's, but if we have this type problem on a Healey, (not unheard of!), then the first thing we do is run up the engine with the radiator cap off the vehicle and check for tail tail signs of air bubbles in the radiator.
This is a normaly a symptom of problems with the head gasket.
As I said I don't know if this applies to TR's.

Good luck. graemlins/savewave.gif graemlins/england.gif graemlins/savewave.gif

03-13-2003, 08:06 PM
Hi, I have never done this before. Hope this is the correct way. I just filled out all the forms and I don't have my glasses,blurry now,plus one finger typer. I have many old 3s,have had overheating a lot, you've done all the right things so far,but unless your engine has been rebuilt, then my bet is rust.Open the drain tap on the block under the carbs. Any flow? Try a wire,jabbed in spout.no flow take it off, try wire agian.no flow open all hoses then back flush at spigot hole with air,no flow,then take off heater tap,air there,you want to work rust back and forth. there are more things to do but I am going blind. If you were to remove the head you would'nt believe the rust betwixt the liners. W

03-13-2003, 08:23 PM
Hi I just reread your problem, whats rebuilt the engine or the rad or both? If both then completly block off the bypass hose, dont need it,recirculates some engine water all the time,also check rad water with candy thermometer,not actual head temp but a good gage,also try Redline water wetter helps a little,so does synth oil. Also need rad air deflector in front do you have one.

Mickey Richaud
03-14-2003, 01:44 PM
Thanks for all the input. I had read about blocking the bypass, and was considering that. Will try that.

Mickey Richaud
03-14-2003, 01:51 PM
OOPS! Hit the wrong key and sent the message before I was finished.

Anyway, EVERYthing was rebuilt, which is why I stumped. I have the small mouth TR3, so airflow shouldn't be a problem. In fact, I can feel air being pulled through the mouth when it's running, so deflector and blade installation are non issues.

As I said, will try the bypass as last resort.

Thanks again for all the input. Anyone going to New Orleans next week?

03-14-2003, 07:41 PM
Hi afew more thoughts, do you have the right depth rad cap, with a 50/50 mix water will expand but should not boil over at 190+, are you sure it is boiling and not just expanding past a too shallow cap and fizzing. Also undo capilary tube and test with boiling water and candy thermom. How many miles on your new engine. Another try is a TR4a six blade fan.By the way you didn't overpaint the rad fins did ya. It's been a very long time since I did story problems. Hope we are graded by the montessory method

03-15-2003, 04:08 AM
Aloha Mickey,

The previous posts have addressed all the areas that can cause overheating. A quick check would be to remove the thermostat and see if it still overheats. While you have the thermostat out, check it with a pan of hot water. With a candy thermometer or an instant read type get the water heated to the same temperature the thermostat is rated at, usually 180 degrees F. PLace the thermostat in the water and see if it opens. If it doesn't open, heat the water to see if it will open and at what temperature. You can also use these thermometers to check the water temp gauge in the dash by comparing it to the water temp in the radiator top tank. THe temperatures should be close, but the cylinder head water temperature (dash gauge) will be higher.

To maintain domestic tranquility, you should probably not use your wife's kitchen tools, but get your own car thermometer(s). I think it is a good idea to check thermostat operation before installing it.

Safety Fast,

03-18-2003, 02:57 AM
I've got a small mouth TR3 and the first thing that I had problems with was the antifreeze mixture. Unless you live in Alaska, you don,t need a strong mix espeacially if your from Florida. I've got a 2.8 Capri V-6 engine in mine and I ended up having the radiator recored with a flat dimpled tubed radiator and the crank hole made solid. So far thats taken care of my problem. If you have foam in your radiator that might be a sign of a head gasket not sealed correctly. Or as it was stated maybe your temp. gauge is faulty. Anyway, Good luck! Jim

Dave Thielke
03-18-2003, 03:20 AM
I know that most of the likely suspects have been covered, but here are a few more unlikely ones.
Check the bottom hose again, I've seen them delaminate so a the inner layer closed off but the outside lookes ok, very rare case.
Some systems require a bleed hole in the thermostat to allow hot water to the other side to open the thermostat. I'm not sure on the TR.
As others suggested, check for flow and bubbles.
There used to be a chemical test for combustion gasses in the coolant, but I can't recall the name of it.
Good luck,
Dave T

Mickey Richaud
03-18-2003, 11:25 AM
Thanks again for all the help. Took the TR3 out Sunday afternoon, and it was flawless - stayed right at 185. When I got home, there was a little foaming out the tube, and I think my problem may well be the cap not sealing properly.

Anyway, it's off to New Orleans for the BMCNO show this weekend. We'll see what happens (No, I'm not driving all the way - gonna trailer it).


03-22-2003, 01:53 PM
Mickey,glad to hear that its better, but the best cure is to look at the root of the problem. The rad is 3 rows deep, that absolutely requires a good fan to pull air through it. The stock fan is a joke, and a poor one at that.If you take the stock fan & cut off the blades you are left with a nearly round hub, find a nice plastic fan such as a tr7 unit, drill and mount it to your hub. On the tr3 you then have to trim the blades a little to clear the steering arms when they turn. this is done with a cheese grater(carefully) while the motor is at appx 1500 rpm. You now will lose 1 point in concourse but you will never be stuck in traffic again even on the hottest day!!!
For a few more $$ you can also bolt on the early tr6 unit, same outcome. Problem solved for good.
MD(mad dog)

Mickey Richaud
03-23-2003, 02:31 PM
MD -

Thanks for the tip. Had thought about changing fan blade, and still may, if the problem persists. As of this minute, it's not too bad...


03-28-2003, 02:49 PM
Hi: The TR3 had a "skirted" thermostat designed to block the by-pass when engine hot. The general consensus seems to be that if a regular type thermostat is used then a large percentage of the coolant never goes through the rad - hence the reason to block the by-pass. Generally it seems that if the by-pass is blocked then a 1/8th. opening should be drilled to avoid problems during the warm-up period. Or ofcourse a "skirted" thermostat can be installed.