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erictr6 Avatar
erictr6 eric l
Denver, NC, USA   USA
After driving around town doing a few errands yesterday, (temp in the low 80's), I parked the 8 in the garage. A few hours later I came out and discovered a pool of coolant on the garage floor.It appears to have come from the header tank overfow tube. Opened the header tank to see how much coolant was left and maybe an inch or so is left in the tank.
Questions
1. What might be the cause of the overflow?
2. What is the correct level in the tank?
3.Can I just add to thetan or is there a procedure to fill it?
Thanks!

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Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, OR, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1377514 by erictr6 After driving around town doing a few errands yesterday, (temp in the low 80's), I parked the 8 in the garage. A few hours later I came out and discovered a pool of coolant on the garage floor.It appears to have come from the header tank overfow tube. Opened the header tank to see how much coolant was left and maybe an inch or so is left in the tank.
Questions
1. What might be the cause of the overflow?
2. What is the correct level in the tank?
3.Can I just add to thetan or is there a procedure to fill it?
Thanks!

Eric:

Nothing special about filling, just pop the cap and pour in fresh 50/50 until the tank is half full. If you lost very much coolant you will need to pour for a while as the excess will run down into the radiator to replenish the coolant there.

As to why it overflowed in the first place, well, something is probably kaput. First thing is to replace the radiator cap with one of the correct pressure rating. IIRC I am running a 13lb cap, but I am not at all certain that is what the factory recommends. Best to check on that one, they are cheap an as you well know installation is trivial. Available at any FLAPS.

If that does not correct the issue, I would suspect the thermostat is on its way out, or perhaps the wrong thermostat is installed. The TR8 requires a thermostat with an air bleed. The recommended 'stat has a 1/8" hole with a tiny check valve in it. While the check valve is nifty, a regular 'stat from your FLAPS with a 1/8" hole drilled in it works just fine. Be certain to install the bleed hole *UPPERMOST* (at the 12 o'clock position) when replacing your current 'stat. Do not try a super low temp 'stat in an attempt to keep the engine cool. Minimum 180F, and IIRC 190F is recommended. I am running 180F and my gauge sits just below the halfway mark when idling.

You didn't say if your car is injected or carb'ed. The next thing is the fan(s). I say next because if the car is boiling over AFTER the car is parked, it is unlikely to be the fans IMHO. If it was overheating in traffic, I would say the fans are very much suspect. After the car shuts down, not so much. If your car is carb'ed, check the fan clutch. Rotate the fan by hand (engine off). It should not free wheel, nor should it be locked. A heavy drag when rotating the fan by hand means the fan clutch is healthy.

If the car is injected, check the fuse for the fans, and start the car and let it idle until the fans come on. If the fans do not come on, or only one fan rotates, you know what you need to do. The fans are 35 years old now, and probably have never been oiled, so it is possible for them to stick. Do not think that you can correct overheating problems by rewiring the fans to operate at high speed instead of the normal low/high speed operation.

Cheers,

Vance



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

darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
If you filled the expansion tank all the way up, that would explain the overflow. As Vance says, it should only be about 1/2 full, as it is supposed to allow for the coolant expansion.

If that wasn't the reason, and you exhaust all the other things on Vance's list, you might have a head gasket issue. The 3.5 using an extra set of head bolts along the side of the head where the exhaust manifold connects. Over time, that can slightly lift the intake side. Usually what happens then is that exhaust gases are vented under the valley pan gasket, but it can also allow exhaust gases to be forced into the cooling system.



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

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Bergie Bob Berg
Powell, OH, USA   USA
My understanding on expansion tank is to open radiator cap engine cold...fill to 1 inch below full...start car idle to warm up...as coolant heats up expansion tank will fill up...when coolant reaches top then re cap and your done....system is pressurized so this bleeds out air from system...only takes 3-4 minutes to fill as car warms up prior to t stat opening...

TeamEvil Avatar
TeamEvil Thomas C
Kingston, MA, USA   USA
Do you have an over-flow bottle beneath the expansion tank?

Bergie Bob Berg
Powell, OH, USA   USA
Yes I have an overflow catch container mounted on other side of car where air conditioner dryer was...canister style moroso I believe....can send pic if you want...need for track days....
Bob

TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
Whats suppose to happen and what really happens aren't the same thing on a wedge, especially an 8. They trap air. It takes a few days and several burping sessions to get the air bubbles into the expansion tank. Those air bubbles will only separate if there is a large enough air pocket at the top of the tank. That tank is never suppose to be full, and shouldn't even be more than half full except for when it is fully pressurized. Initially fill it about 1/3 to 1/2, drive until it warms, burp out the air carefully, add fluid if needed... preferably adding when its cold. I've seen them completely empty and the car runs fine, but empty starts the guessing game of how much fluid is really in the system. Going to larger radiators is common. Problem with that is there is a greater volume of coolant in the system and a need for a larger capacity reservoir. If you go to a larger radiator, you need to have even less fluid in the reservoir when the system is cold. You need room for expansion. The cooling system works very similar to a house's hydronic boiler heating system. You need room for the liquid to expand, or it builds pressure and dumps excess volume of liquid. You can't compress a liquid, but you sure as hell will expand it when you heat it up. Thats why house systems all have expansion tanks. A typical house will have a tank that can account for an expansion of close to 2 gallons in volume.

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Mr. Nuts Peter N
Tucumcari, NM, USA   USA
Sounds to me like you have an open system with enough parts already installed to make it a closed system. A simple closed system radiator/expansion tank cap and you would not have to be concerned with proper levels in the expansion tank as it would be full all the time with the proper sized over flow tank.

erictr6 Avatar
erictr6 eric l
Denver, NC, USA   USA
It's been a while and a few things were changed. First we noticed a leak in the lower right corner of the radiator. Took it out, had it pressure tested and found the leak and one more, flushed and cleaned and reinstalled. Once again, another leak. At this point I decided to invest in an Woody's aluminum radiator, Maradyne fan and new radiator cap. That solved the leak and overflow problems and the engine runs much cooler, needle below halfway mark. Returned radiator to the shop to repair the leak. Have strip the old paint, primed and repainted with Eastwood radiator spray paint. Will put up for sale along with dual AC electric fans. Please PM if interested.

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erictr6 Avatar
erictr6 eric l
Denver, NC, USA   USA
Here is why the coolant overflowed from the header tank.

Did block test for possible blown head gasket - negative, but only ran for a minute due to coolant overflowing from header tank

1. previous 180f thermostat without jiggle pin - dont think that was the primary cause since never experienced this issue before, but changed to a new 180f with jiggle pin
2. After new stat still running hot and noticed the Maradyne fan cycles on and off too soon, so replaced the high speed temperature switch. Fan comes on and stays on when AC pressure reaches 250 lbs and coolant temp of 197f
Did longer block test for possible blown head gasket - negative
Temp gauge reads low replaced sending unit and recheck. Still low at 1/4. test drive got into traffic jam on interstate, gauge up to almost 1/2 with AC on. Arrive home shutdown and coolant stayed in system. No overflow through tube.
Another issued crossed off the list. Next replace ball joints and tie rod ends!

Looking for a money machine, please advise if you have a used one!

Andrew1966 Andrew Ward
Abbotsford, BC, Canada   CAN
If you change to evans waterless coolant you will have no overheating issues. This coolant has a boiling point of over 350 degrees so there is no expansion and no pressure build up. It is more expensive than pre mix coolant but once you change it that is it for life. It also extends the life of all your hoses prevents gaskets from leaking due to pressure and is an excellent corrosion inhibitor.
Jay Leno wha has a vast expensive car collection uses evans in all his cars.

darrellwalker Darrell Walker
Vancouver, WA, USA   USA
1966 Triumph TR4A "Christy"
1981 Triumph TR8 "Kate"
In reply to # 1503961 by Andrew1966 If you change to evans waterless coolant you will have no overheating issues.

I think it is more correct to say "no boiling over" issues. The Evans coolant doesn't cool as well as water/antifreeze mix (and straight water is even better).



Darrell Walker
66 TR4A IRS-SC CTC67956L
81 TR8 SATPZ458XBA406206
Vancouver, WA, USA

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
In reply to # 1387920 by Mr. Nuts Sounds to me like you have an open system with enough parts already installed to make it a closed system. A simple closed system radiator/expansion tank cap and you would not have to be concerned with proper levels in the expansion tank as it would be full all the time with the proper sized over flow tank.

Exactly what I have done. I have simply run the small hose that originally comes off the header tank and goes through the inner fender to the BOTTOM of my overflow bottle. Then a similar hose runs from JUST UNDER the lid of the overflow bottle through the original inner fender hole. Now I have a telltale system that shows coolant level and the header tank is always full.http://www.triumphexp.com/phorum/read.php?3,1471791

Post #4, 2nd photo. http://www.triumphexp.com/phorum/read.php?3,1471791

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