Air in the system and losing Coolant

[Chunkychops]

Hi guys,
A bit long winded this one but any help would be appreciated. My coolant light kept coming on but when I checked the header tank the level was fine, but the bottle was cool to the touch, as was the top hose going to the rad. And I noticed there was little or no water in the bottom hose going from rad to engine.
I'm running a Davies Craig electric water pump which is fitted inline to the bottom hose a few inches from the rad so it seems to be pumping fresh air. The warning lights on the pump control unit kept coming on indicating a problem. Despite the bottle being near full I was able to get about 4-5 lires of coolant into the system.
This seemed to cure the problem, but then a week or so later the warning lights came on again and.. same problem, hardly any water in the system. I let the engine idle with the heater on for about 40 mins with the cap off to allow any trapped air to escape. There was some bubbling but there is clearly still air in the system that I cant get rid of and coolant loss. Ive checked all the pipes and connections and found no leaks. I flushed out the radiator and fitted new hoses when I fitted the electric pump unit last year so its unlikely to be a blockage. Any ideas? Should I try filling the system through the thermostat housing? (Thermostat has been removed as control unit manages the coolant temperature).

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[Paul_TR8]

The best way of filling is to remove the thermostat and housing and fill, you then can fit the thermostat and top up the header tank, to check for a leak I would suggest a pressure tester,
Also strange ad it may seem check the engine oil level just in case the head gasket has blown and the coolant is going into the oil

JRV459X TR8 DHC EFI Cashmere Gold
UPK688S TR7 FHC Auto Inca Yellow
TCK162P TR7 FHC New White
TFX458R TR7 FHC Pimento Red
NDP505X TR7 DHC Triton Green
XCK645R TR7 FHC Inca Yellow VICTORY Replica?

[saabfast]

4-5 litres is a lot to lose and, assuming it is not going out of the bottle expansion/overflow pipe and there are no leaks (ie into the cabin from the heater matrix, are all the carpets dry?) it could well be the head gasket as suggested. Check the plugs as well as the oil as it could be a waterway leaking into a bore. This would normally pressurise the cooling system when running and force water out of the overflow pipe.

Alan
Saab 9-5 2.3t Vector Auto Estate
'81 TR7 DHC

[Cobber]

Contact Davies-Craig http://www.daviescraig.com.au/ContactUs.aspx for support, I always found them very helpful.

Your not meant to use a thermostat when you use a Davies-Craig pump as the electronic control unit of the pump now does the job of the thermostat.


"Keep calm, relax, focus on the problem & PULL THE BLOODY TRIGGER"

80'Triumph TR7, 73'Land Rover (Ford 351. V8),
'89 Ford Fairlane
'98 MG-F, 69'Ford F250.

[Stag76]

With an EWP Fitted, the air-lock problem no longer applies, as the entire block and inlet hose is pressurised.

If there are no external leaks (radiator, heater matrix, hoses etc) it sounds like the head gasket may have failed.

Remove the plugs after an overnight cool-down, (shouldn't be a problem at this time of year) and, if any of them have the appearance of being steam-cleaned, it may indicate a leak into that cylinder.

While the plugs are out, spin the engine on the starter and check for coolant being expelled from the cylinders.

TR7 Convertible
Sprint Motor
MegaSquirt EFI

[FI Spyder]

With having to add 3 to 4 litres which seemed top temporarily solve the problem the coolant has to go somewhere. I can't see it being blown out the overflow pipe as if there is air in the system it is the air that will get blown out, not coolant except for that coolant that is part of an overfill which get expelled as the volume increases with heat but that will only be about 1.5 from the top of the expansion tank when full (Hasbeen has different description of the action/name of the tank but we'll call it that for now). If 3 to 4 litres went into the crankcase you would certainly know about it (light brown milkshake looking oil as well as elevated oil level at dip stick). This leaves sucking coolant into the combustion chamber and being discharged out the tail pipe to disappear and dissipate into the atmosphere. You should be able to see white smoke (steam) coming out the tailpipe (not to be confused with normal water vapour condensation when the engine is not up to temp and the exhaust pipes are still cold). If this is the case, a blown head gasket between water jacket and combustion chamber and possible head warpage.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

[sonscar]

Not being very familiar with the TR7 angine I am wary of the thermostat removal.On A and B series engines of the British Leyland stable removal of the thermostat has to be supported with a restrictor of some sort to promote proper circulation of the coolant to prevent localised boiling.Of course the TR7 engine may not be prone to this so I could be scaremongering unnecessarily.Does the system hold pressure?Hope you find the answer,Steve..

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[Chunkychops]

Thanks for the replies, Ive not noticed any white smoke atall. I had a head gasket go recently on my old Mini which did that.

Last year I dropped the sump and there was about half a cup of water in with the oil. And theres always been a bit of mayo on the dipstick since I bought it about 4 years ago but its always run fine and done a fair bit of mileage in that time.

Hope its not the head gasket as we all know what fun that is, but thats about the only thing that hasnt failed yet.

Will do some investigating and get back.


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[Chunkychops]

The oil level on the dipstick is definitely high, an inch or so past the max mark and some mayo present, but theres always been a bit of mayo on the dipstick for as long as ive had the car. I removed the plugs and noticed that pot 1 and 2 plugs are black and sooty, whereas 3 and 4 are clean looking, just a bit light brown.

The carpets are a bit wet both sides but it looks like condensation forming on the cold metal of the footwell rather than a leak. Anyone else get this? Not noticed any water escaping from the exhaust, not paticularly smokey either. I spun the engine with the plugs out and theres no coolant expelling from the bores. I loosened a hose to let a bit of water out to see if it was oily but it wasnt.

If it is the head gasket would it be worth trying http://www.steelseal.co.uk/ ?

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[sonscar]

Take it somewhere to have the coolant tested for combustion products and/or have a leakdown test performed to try and put your mind at rest.Steve..

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[Hasbeen]

When we had water getting into the sump of the 8 we were advised to jack the engine up enough to remove the sump, then pressurize the cooling system.

It was great advice, as we found no head gasket problem, but water leaking into the timing cover area,

A hassle getting the sump off, but a much easier job & fix, than pulling the heads off, only to find they were not the problem.

Hasbeen

[bobC]

Hi Chunky

I've got the Davies Craig EWP fitted too and I've never had any issues with air locks. In fact I've had no issues whatsoever with the cooling system since it was fitted, other than the engine running too cool when driving at speed. I've also removed the thermostat and fitted a restrictor in the bypass. I normally fill the system via the header tank and run the pump for a few minutes with engine off - this seems to expel any excess air.

If its not a head gasket issue and you've definitely got coolant in the oil, then I'd check the bung that replaces the mechanical water pump. Its an easy check to do before you go removing the sump/head/etc.

The bung is unlikely to jump out easily especially if the bolt is in position and in contact with the roof of the water pump manifold - but you never know.