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TR8 Overheating

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Jeffyoung Jeff Young
Raleigh, North Carolina, USA   USA
34,000 original mile TR8. I got it at 33,000 ater it had sat or a decade. Got it running, ran pretty well. Did have a water pump failure. REplaced that.

Car ran good for a few weeks. Spirited Sunday drive and the temp gauge, after about 2 hours of driing, just sddenly went to full H. Got the car home. Car will start, idle fine, t-stat opens but no dice on coolng. fans on but the gauage just steadily climbs to H.

I'm assuming head gasket failure?

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ozkippy Michael Kip
Emerald, Victoria, Australia   AUS
1976 Triumph Stag "Staglet"
1978 Triumph TR7 "Yellow Wedge"
1979 Triumph TR7
Jeff,
We all imagine the worst but in this case I would consider some other things first.
Clogged radiator. With the engine cool start it and watch the gauge while feeling the top and bottom radiator hoses . Gauge gets hot then turn off, as alloy engines don't like getting really hot, and feel if there is a difference in how hot the top and bottom hose feels. Top hot bottom not so much then I would look at a clogged radiator. If that case then off to the local radiator shop to get it rodded out properly or replace with an aftermarket one. Recently there have been a few threads on this forum on aluminium radiators from Summit .
If the radiator seems to be quite consistent warm hot over its whole matrix with that test then look for bubbles in the coolant which would indicate a Head Gasket issue. There is a test you can carry out to detect CO in the coolant and about which there are videos on YouTube.
If you needed to do the water pump and the if the radiator is in need of repair then I also would consider getting a propitiatory engine coolant flush or as a minimum flush out the engine block with a pressure hose. Again lots of You tube videos on that .

Try the easy stuff first before worrying too much about having to repair a Head gasket . smiling smiley

Michael

Cheapsnake Avatar
Cheapsnake Tom Soik
Sturgeon Bay, WI, USA   USA
The cooling systems on these cars are marginal even at their best. I got my TR8 at 32K miles and went through pretty much the same experience as you, eventually actually seizing the engine. Surprisingly, it started right up after cooling down and never showed any ill effects from the experience. Don't recommend it though.

I went through a series of fixes, starting with the removal of the AC condensor (helped a bit), followed by a new water pump (no help at all), followed by a new 14" fan (oh what the h*ll). The one thing that made a significant difference was the installation of a 2-row aluminum radiator. BIG difference. Now I can drive with both eyes on the road vs. one on the temp gauge. Not a real tough job and plenty of good info on the forum from those that have done the switch. Good luck.

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Bergie Bob Berg
Powell, Ohio, USA   USA
I would replace the thermostat....cheap and easy to do...then move to radiator.....

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1450516 by Bergie I would replace the thermostat....cheap and easy to do...then move to radiator.....

I second Bergie. The only time my TR8 overheated was when I had installed a new thermostat. A couple of days later it boiled over while idling. Another new thermostat cured it, so my first new t-stat was bad right out of the box.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

Bergie Bob Berg
Powell, Ohio, USA   USA
Don't skimp on the thermostat with cheap one...not worth the time and effort to replace again....I use EMP/Stewart high performance tstat #301 with bypass holes so coolant is always flowing...stick it in a pot of boiling water with a cheap autozone one and you will see the difference...also use permatex blue RTV silicone lightly on the housing gasket both sides....

Bergie Bob Berg
Powell, Ohio, USA   USA
also check your engine grounding strap...take it off clean and put back on...when you loose ground gauges read higher...there is also an instrument cluster ground you can check...make sure wire contact on the temp sensor is clean and in contact with tab...

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tr7v8mike Avatar
tr7v8mike Gold Member Michael Booth
SYDNEY, NSW, Australia   AUS
I'm having overheating problems, too, but they're probably different. Around town the car is fine, but on a hot day I can't drive above 90km on a freeway. I got pulled over by the cops yesterday, wanting to know why I was driving so slowly. So f...... embarrassing! I won't tell you the conversation I had with the female cop who looked about 16.

The new engine generates so much more heat than the old one. The radiator is clean, I have integrated electric water pump and big fan and they come on when they are supposed to. The engine is a rebuilt Rangie. I'm pretty sure the radiator is just not big enough.

The question is alloy or copper. I've read heaps about the alloy ones falling apart after a few months due to electrolytic corrosion. Is there any way to guarantee that there is no stray current flowing into an alloy radiator?

Mike

Bergie Bob Berg
Powell, Ohio, USA   USA
Sounds like radiator but a few questions....do you have air conditioner/condenser blocking the radiator, which radiator are you running TR7 or 8 with or without ac, is it the original water pump to rover v8 and explain the electric water pump in the system...what is inside diameter on the pump because if it's less than 1.5 inches (hose diameter I presume) you will have reduced flow at high RPMs and have overheat situation....also when you are running on highway if you put on heater full hot with fans on high does that bring down temp gauge?
Bob

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tr7v8mike Avatar
tr7v8mike Gold Member Michael Booth
SYDNEY, NSW, Australia   AUS
Hi Bob,

Yes, I have A/C (Vintage Air). I'm not sure about the difference between 7 and 8 radiators, but its the biggest that will fit in the space so I guess its for a TR8. The EWP is from Davies Craig and takes the standard hose. It sits just off the radiator outlet. No mechanical pump. Turning the heater on was the last thing I was thinking of, but the temp went up and down with the speed. I never had any problems when I had the 3.5L engine in.

tr7v8mike Avatar
tr7v8mike Gold Member Michael Booth
SYDNEY, NSW, Australia   AUS
There's more than the usual volume of rubbish on the web about preventing corrosion in an alloy radiator. I think I've gleaned a couple of facts:

Use de-mineralised water
Don't mix coolants
Use only the recommended coolant
Isolate completely with rubber mounts
Having an alloy block is a significant advantage

Hopefully someone who knows what they are doing can set me on the right path. No alternative facts or fake news, please.

Mike

ozkippy Michael Kip
Emerald, Victoria, Australia   AUS
1976 Triumph Stag "Staglet"
1978 Triumph TR7 "Yellow Wedge"
1979 Triumph TR7
Michael,
Alloy engine may well be a problem with a Copper radiator due to Copper and Aluminium being not very close on the Galvanic table. Hence the use of a suitable coolant that works for a greater temperature range by increasing the boiling point along with the pressurized system in the radiator etc but also an inhibitor to lessen the galvanic reactions between dissimilar metals. That manifests itself in the 8 valve more with its cast iron block and alloy head than your all alloy Rover V8 . Copper radiator would require the inhibitor but an aluminum radiator would have much less of an issue in your case.
You're in that den of iniquity Sydney with , dare I say, pretty good water in the mineral sense so using demineralised water may well be an indulgence to my mind. Far be it for me to say that Sydney and Indulgence belong together so take that observation with a grain of salt hahaha. Oh dear I will get in trouble with my sense of humour hey. Out west from you with bore water etc perhaps using distilled / demineralised water would be a worthwhile proposition.
There is something wrong if your large clean Aluminium radiator , clean coolant system along with your electric Davies Craig pumps is not able to keep the engine cool. Question!! The discontinued water pump !!!!! Is it still in line but not turning or has it been gutted with just the outer case?? Twill be a simple thing like that which may be slowing coolant flow through your engine perhaps.
Do you have the whole she bang Davies Craig pump / fan with the controller that varies water flow dependent on temperature?? Looks like a really nice system is all.

Porsche 4 hour next Sunday at Sandown so the excitement builds hahaha. Staglet will cop a flogging !!! Vroom Vroom. All Triumph weekend Wakefield July 1st and 2nd so time to get the skates on hey?? Hope to say G'Day then.
Hey GWS flogged the Swans how good is that?? Saints supporter here sadly so a season 6 weeks old and already a forlorn hope hahahaha


Michael

tr7v8mike Avatar
tr7v8mike Gold Member Michael Booth
SYDNEY, NSW, Australia   AUS
Hi Mike,

No, I don't have the alloy radiator yet. Its the old copper radiator that's not doing the job. PWR have a branch in Queensland and I've just emailed them. I looked into having one shipped from the US or UK and based on the shipping costs it looks like they are going to send it as the only parcel on a private jet. Yes, I have the whole Davies Craig setup with the data readout mounted up on the dash, beside the oil pressure gauge, just below my eye line. I pulled the impeller out of the old pump so it didn't interfere with the coolant flow.

I'll do my best to get to Wakefield Park, should be a really good day. You seem to have a nasty, but understandable, case of Sydney-envy going on there, mate.

Mike

ozkippy Michael Kip
Emerald, Victoria, Australia   AUS
1976 Triumph Stag "Staglet"
1978 Triumph TR7 "Yellow Wedge"
1979 Triumph TR7
Hahahaha.
Yeah but you have that lovely harbour while we have a river that flows upside down with the mud at the top. No envy at all haha smiling smiley

I bought an el cheapo Aluminium radiator off Ebay a little while ago that fits like it was meant to go in place. I think for a WRX or some such!! Cheap as as this man is as cheap as. !! I just needed to glue on the locating lugs along the bottom runner using a Poly urethane sealant glue. May be worth a look is all.

Michael

ozkippy Michael Kip
Emerald, Victoria, Australia   AUS
1976 Triumph Stag "Staglet"
1978 Triumph TR7 "Yellow Wedge"
1979 Triumph TR7
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