Cooling woes

[bigmalcy]

Hi guys

Looking for some advice regarding a cooling system issue, which I haven't had a chance to investigate yet.

I drove the TR back from NSW to VIctoria the other day (500 mile trip) and ended up limping home with 2 litre coolant top-ups required every 30 miles or so for the last 100 miles.

First issue I noticed was needing to top up approx 500ml of coolant after the first 100 miles... then the heater went stone cold... then the temp guage started creeping up above its usual position at just below 185.  When this happened, I stopped to check coolant level and that was when I started the regular top ups to get home.

Bear in mind the ambient temp was less than 10 deg C (pretty chilly!) and I was cruising at 55mph, albeit without overdrive (that's another story!).  The gauge never got above the mark between 185 and 230 (not sure what that actually equates to?).  

I don't think the engine overheated at any point.  It was running fine throughout, and the temp check thingo on the cylinder head looks to confirm that it hasn't got to more than 99 degC.

I'm wondering if it might just be that the radiator cap has failed - I can't see any obvious sign of leaking from hoses etc, and no sign of water in the oil or out the back.  The overflow tube was also noticeably hot and there were signs of coolant coming from that cap area (wasn't sure if that was from my re-filling though). 

Would a failing radiator cap reduce the pressure in the system such that flow through the heater would be cut off?

Thanks in advance!

PS - photos show the start of the journey which was very lucky... for once the boys in blue gave me a slap on the wrist instead of a hefty fine!

[Lebro]

I would be looking for external leaks first, (hoses etc) I doubt the rad cap is to blame.

Bob

[iain]

That’s quite a loss.

This is my check list

let it run up to normal temperature, bonnet open having carefully filled the radiator header tank so that it’s about 1/3 full. No more, this is the expansion tank. If you fill brim full it will just spit it out as soon as you get to normal temperature. (If I’m teaching you to suck eggs on this apologies, but many overfill.)

check all hoses.

check the stat is opening at the correct temperature, check the cap and overflow are not issuing water at normal temperature, your observation suggests they will.

check the heater control valve is open and not weeping around the gland.

check the radiator expansion neck has not fractured where it attaches to the top tank. You can loose  a lot of water at this joint and barely see witness marks. However on a static test, you will see steam coming of the radiator at normal temperature if it’s leaking.

Check for water in oil

check for water pushing up around the head studs.

I am sure others will have other checks as well.

Good luck

Iain

[Ralph Whitaker]

The heater not working is due to an air lock, and the symptoms you describe seem to me that the water is being displaced and forced out of the radiator (hot overflow pipe!) which I am pretty sure would indicate a failed head gasket (sorry).  See if you can get your hands on one of the test kits that check for combustion gasses in the water. Also pull the spark plugs and look for condensation on the plugs. I hope for your sake  I am wrong, 

Ralph

Edited May 20, 2023 by Ralph Whitaker
spelling mistake

[iain]

42 minutes ago, Ralph Whitaker said:

The heater not working is due to an air lock, and the symptoms you describe seem to me that the water is being displaced and forced out of the radiator (hot overflow pipe!) which I am pretty sure would indicate a failed head gasket (sorry).  See if you can get your hands on one of the test kits that check for combustion gasses in the water. Also pull the spark plugs and look for condensation on the plugs. I hope for your sake  I am wrong, 

Ralph

Could be correct Ralph, but so far there appear to be no other symptoms supporting that diagnosis. 

[keith1948]

Heater not working could be the valve or airlock but might it also be faulty water pump or thermostat. Make sure the water pump doesn't seize when it gets hot or the fan belt is slipping. Other things to look for maybe collapsed hose or blocked radiator core. Check all the things that Iain has listed. Get it up to temperature, turn off the engine and then look for steam or fine spray of water from a pinhole somewhere. It is safer with the engine not running as well as not having the fan blowing away any fine steam traces.

Hopefully not a cylinder head gasket but that can be fixed. Crack in the head or block is another matter - I won't think about that.

Good hunting

Keith

[roy53]

Thermostat for me but check that the top of the rad is flush where the cap sits. just run a flat file over the area it will show up any slight dip in the brass neck. Found this a few times.

Do you know if you have a restrictor in the pump housing or pipe bypass hose part 25 moss cat.

Strange that it was ok for 400 miles though.

Roy

[Ralph Whitaker]

I would expect both a failed thermostat or faulty water pump to cause overheating, same with a collapsed hose or blocked radiator, but Malcy says that was not the case. 

Only needs a very small leak at the head gasket to pressurise the cooling system and force water out of the overflow pipe, especially if it has a 4lb radiator cap, and if the leak was into the water jacket you would not see water in the oil.

Ralph

[Lebro]

If the head gasket is under suspicion, then 1st step would be to re- torque all the head stud nuts. Back off each in turn (following the normal sequence) till the nut moves, then tighten back up to specified torque.  Doing this cured my slight pressurisation of the coolant.

Bob

[Nigel C]

just a heads up, if you experience lose of water on the road and have to keep topping it up, leave the rad cap off. If the water system is not pressurised then you will lose far less water...I know its there for a reason (raising boiling point and all that) but you will have more over heating problems if lose the water than the difference pressurisation can offer

If its a head gasket problem then the cap won't help anyway as the pressure will be greater than the cap....IMHO of course.....

[keith1948]

On 5/26/2023 at 8:38 PM, Nigel C said:

just a heads up, if you experience lose of water on the road and have to keep topping it up, leave the rad cap off. If the water system is not pressurised then you will lose far less water...I know its there for a reason (raising boiling point and all that) but you will have more over heating problems if lose the water than the difference pressurisation can offer

If its a head gasket problem then the cap won't help anyway as the pressure will be greater than the cap....IMHO of course.....

Hi Nigel

Leaving the rad cap off is a very good tip I had almost forgotten about. Used that trick several times on my Austin Mini when the by-pass hose had split.

Keith

[bigmalcy]

Hi guys - resurrecting a very old thread here: a sign of my time-poor stage of life.  Thanks for your observations and suggestions so far.

Anyways - long story short, I dug into the cooling system today, partly to trouble shoot the coolant loss and non-working heater issues, partly to do a clean and flush of the system. 

What I found:

- heater circuit confirmed to be clear and not blocked.
- drain at bottom of radiator didn't drain until I poked something into it... then it ran quite clear
- cylinder block drain similarly reluctant to drain, but a wire up the guts got it going.  Seems odd that the valve is open when the handle is pointing away from the block... would have thought it should be the other way around?
- Most significantly: I removed the bypass hose and lo and behold, the restrictor thingo I put in there all those years ago with 5mm aperture was gummed up.  It came clear with a few pokes of a screwdriver, but I had just taken the care for a spin around the block, so it was blocked securely enough to stop flow. 

After driving the car around the block and properly warming the engine, the bypass hose was cold (still blocked at this point) as were the hoses leading to / from the heater core (especially the one on the UK passenger side - stone cold).  Obviously no heat coming from the heater.

Also - as before, no sign of any coolant leaks, anywhere.  The car ran up to temperature, the fan cut in and turned off as usual.  I noticed that the temp gauge immediately dropped after the car was started 'hot'... which I take as a sign that the thermostat was open.

Unfortunately, the bypass hose was cracked, so I was unable to complete my flush and replenish work and then re-test the system to see if things were back to normal (i.e. all hoses warm, heater producing heat).

 

SOOO..... the question for the collective: would a blocked bypass hose impact on flow through the heater circuit?  Would it lead to coolant loss when running at steady high engine rpm (say 3000)?  Would it cause any damage to the engine on its own?  Note that the engine seems fine - starts relatively easily, no obvious sign of distress anywhere (smoke or sounds, and the temp indicator thingo on the back of the block still shows that it hasn't got 'too' hot.

A quick Google search suggests that the blocked hose should not have been too much of an issue, if any issue at all... but I am desperate for it to be the source of my coolant loss / defunct heater issues.  Perhaps the heater issue is instead due to a clogged internal passage, given the drains were reluctant to run until I gave them a 'poke'?

As always - your thoughts appreciated!

 

[ianc]

I would be concerned at the **** which blocked both drain cocks and the bypass hose - and possibly the heater circuit.  Suggests that the whole inside of the water system needs to be thoroughly cleaned, then filled with 25% antifreeze, changed every 2 years (or Evans Waterless, which doesn't need to be changed).

Heater circuit can be purged using a hand-held water pump, or, if careful with the pressure, a hose from the mains.

Drain cocks: there seem to be two types, one with cock open when lever aligned to flow, the other opposite - can be very confusing!  My brother had a TR3 on which we found the cock on the cylinder was open - but there was so much **** in the block that no leakage could occur.

Ian Cornish

[Ralph Whitaker]

As the by pass hose exists to allow water to circulate through the engine until the thermostat opens to allow the water through into the radiator, the heater circuit returns it`s water to the back of the pump, which would then send it through the by pass hose to circulate again, so a blocked by pass would certainly have a detrimental effect on the heater.

Ian has beaten me to it, I was about to say also that it sounds like a good flushing is in order.

Ralph

[BlueTR3A-5EKT]

Did you re torque the cylinder head yet?

Blocked bypass is a problem.   open the hole up to 8 mm min.   Marco proved this dimension and it is less likely to ‘crud up’.
 

The water system will not always self fill from cold up to the thermo housing as you have a thermostat blocking the route through, unless you have a modern thermostat with a bleed valve in it.  Even then the 2-3 mm hole will take an age to vent through to the top hose and header tank of radiator.    With the bypass blocked it is even more reluctant    I added a screwed in vent valve to my thermo housing to be sure to get water into the housing when refilling the system.    Once the thermostat opens all the air and water will purge itself through.

I disconnect the heater return hose from the block to pump pipe with the rad cap removed, water filled to the brim and the engine cold.   Start engine , pull off hose, Put your thumb over the block pipe and point the hose downwards, That sees a flow of water from the heater, reconnect and re clip when there is a steady flow.    That will have purged the heater.   Do this cold!   Without the pressure cap.

ohh and retorque the cylinder head if it has not been done since the engine was built.

 

Edited March 2 by BlueTR3A-5EKT

[Motorsport Mickey]

"ohh and retorque the cylinder head if it has not been done since the engine was built."

I would do this even if the head has been retouqued, previously.

The head gaskets if copper tend to still compress over the years, and it's not unusual for a retorque to "gain" a little where the head gasket has relaxed. Ohh ...make sure you UNDO the head nuts by 1 flat first, to avoid stiction (sticking friction where the nut has stopped) compromising the retorque. don't be surprised after loosening the 1 flat if the nuts wind up by some amount more than where they started from. 

Mick Richards

 

[John McCormack]

17 hours ago, ianc said:

I would be concerned at the **** which blocked both drain cocks and the bypass hose - and possibly the heater circuit.  Suggests that the whole inside of the water system needs to be thoroughly cleaned, then filled with 25% antifreeze, changed every 2 years (or Evans Waterless, which doesn't need to be changed).

Heater circuit can be purged using a hand-held water pump, or, if careful with the pressure, a hose from the mains.

Drain cocks: there seem to be two types, one with cock open when lever aligned to flow, the other opposite - can be very confusing!  My brother had a TR3 on which we found the cock on the cylinder was open - but there was so much **** in the block that no leakage could occur.

Ian Cornish

We've had a couple of bad experiences with the Evans waterless coolant.

Cars have overheated for whatever reason and, as the coolant doesn't boil and the driver isn't checking the gauge, the engines got hot enough for the oil to break down. Two badly siezed engines.

I've been recommending owners not to use it. 

I'd be interested in any stories on its use over there.

[stuart]

10 hours ago, John McCormack said:

We've had a couple of bad experiences with the Evans waterless coolant.

Cars have overheated for whatever reason and, as the coolant doesn't boil and the driver isn't checking the gauge, the engines got hot enough for the oil to break down. Two badly siezed engines.

I've been recommending owners not to use it. 

I'd be interested in any stories on its use over there.

Banned for racing use in the US as under pressure it will ignite. Also upsets calibration on EFI systems. Very difficult to remove once used too. I would never use or recommend it, just removed it from a TR5 and owner much happier now as his heater works properly again.

Stuart.

[ianc]

I have had no problems with Evans Waterless Coolant, and Neil Revington uses it.

There are 4 smaller gauges on the dashboard of my TR, and they are there for good reason, so  I scan fairly frequently. 

If one knows what each gauge should be reading, scanning should be very rapid.

Ian Cornish

[bigmalcy]

On 3/2/2024 at 10:57 PM, Motorsport Mickey said:

"ohh and retorque the cylinder head if it has not been done since the engine was built."

I would do this even if the head has been retouqued, previously.

The head gaskets if copper tend to still compress over the years, and it's not unusual for a retorque to "gain" a little where the head gasket has relaxed. Ohh ...make sure you UNDO the head nuts by 1 flat first, to avoid stiction (sticking friction where the nut has stopped) compromising the retorque. don't be surprised after loosening the 1 flat if the nuts wind up by some amount more than where they started from. 

Mick Richards

 

Hi Mick (and Peter) - being super lazy here, is there a good Idiots guide to the re-torque process that you can link me to?  Thinking mainly about torque settings and order.  It hasn't been done since the engine build... about 2,000 miles and 11 years ago.

[bigmalcy]

On 3/2/2024 at 8:13 PM, ianc said:

I would be concerned at the **** which blocked both drain cocks and the bypass hose - and possibly the heater circuit.  Suggests that the whole inside of the water system needs to be thoroughly cleaned, then filled with 25% antifreeze, changed every 2 years (or Evans Waterless, which doesn't need to be changed).

 

Hi Ian (and Ralph), I agree with the concern re crud... I'm honestly a little (or a lot!) ashamed that I let it get to that stage.  Anyway - on checking the heater outlet valve I discovered that the little branch pipe that connects to the hose was blocked in a similar fashion to the bypass hose... now it is clear and I can blow down that pipe and out the radiator cap.  I am waiting for a replacement bypass hose to arrive from Queensland and then will do a good clean of the cooling system before a coolant refresh.

 

On 3/2/2024 at 8:15 PM, Ralph Whitaker said:

 the heater circuit returns it`s water to the back of the pump, which would then send it through the by pass hose to circulate again, so a blocked by pass would certainly have a detrimental effect on the heater.

I thought that the flow through the bypass hose was from the thermostat housing back down to the pump, not from the pump to the housing... am I wrong?  As above, the heater issues was likely caused by a blocked pipe downstream of the cylinder head valve.

[Ralph Whitaker]

 

5 hours ago, bigmalcy said:

 

I thought that the flow through the bypass hose was from the thermostat housing back down to the pump, not from the pump to the housing... am I wrong?  As above, the heater issues was likely caused by a blocked pipe downstream of the cylinder head valve.

  I think you are right, so the water from the heater gets sent around the engine again . I suppose this helps the heater warm up quicker (assuming no blockages).

Ralph

[BlueTR3A-5EKT]

6 hours ago, Ralph Whitaker said:

 

  I think you are right, so the water from the heater gets sent around the engine again . I suppose this helps the heater warm up quicker (assuming no blockages).

Ralph

502602 WSM Cooling (dragged).pdf

 

Schematic of water flow in TR engine from WSM

 

[Z320]

Hmmmm, my calculation is you topped up 2 liters at all.

First 0.5 liter, next in several stops for example 5 times 0.3 liter.

How do you notice the loss of 0.3 liter coolant while you drive a TR?

Ciao, Marco 

 

[bigmalcy]

 

11 hours ago, Z320 said:

Hmmmm, my calculation is you topped up 2 liters at all.

First 0.5 liter, next in several stops for example 5 times 0.3 liter.

How do you notice the loss of 0.3 liter coolant while you drive a TR?

Hi Marco - I know that I topped up 2 litres several times over... I was pouring the water in using a two litre soft drink bottle!

I couldn't detect the water loss from the driver's seat... what I noticed was the temp gauge creeping up above where it normally sits: that was the red flag.