coolant problem

[roy666]

Hi Guys, recently replaced my radiator, took half an hour to fit and then 2 hrs to line up all the bolt on the support frame. But very pleased with it and its working well, temp gauge on a usual run is only very slightly down. That was a week ago. Now a have major issue with the coolant. Drove back from Scotland yesterday, hard drive, lots of high revs, after about 4 hrs non-stop driving the temp went right up pass the ¾ mark and I didn’t notice until the engine warning light came on. I stopped and the coolant was hissing out of the resovoir under serious pressure and it was totally full of coolant. I let it cool down, all the coolant in the res disappeared. I topped it up with water(always carry some), started the engine. The coolant level in the res went down a bit, then surged up, then went down a bit, then surged up… did this 3 times and then overflowed the res. I messed about a bit more but I could´nt get the coolant to flow properly. Fortunately, I was not too far from home and a mate came and towed me home. Left it for the night. This morning… topped up res again… engine on, started fine,.. same thing happened.
- I thought stuck thermostat… so removed it and tried again. Still surges up and finally overflows. By now all the blue coolant has thinned out so much its just water.
- I topped up again and did it with the res cap on tight; water surges up and fills the entire res tank with lots of air coming through the air bleed pipe from the engine. Engine gets hotter and hotter!
- I noticed the heater in-pipe (one with the vacuum valve on it) was v hot, while the out-pipe from the heater matrix was just warn; turned on heater air to max, just warm air when it should be v hot. Ok, so know water getting up to the matrix… no surprise there.
- I also noticed that the radiator was just warm, lower pipe hardly hot at all. So no water getting to it. Water pump on the engine was new on last service 1 month ago when the cam belt was changed.

- What the hell is going on?

[John_W]

Have you bled the system using the valve under the LHS light pod?
That's the only cheap solution I can think of before I start thinking about gasket failure and it gets expensive.
Good luck.
John

[dapinky]

The radiator can hold quite a lot of air and needs to be bled fully (often 2 or 3 times) after any major cooling work.

[Simon_P]

New head gaske required, or the impeller has fallen off the water pump.

[roy666]

I did bleed the rad, but only once. Then drove it for a week and the temp was fine. Are you suggesting an air lock was in the system and has moved to now block the whole circulation? I´m bleeding the system now and all I get is water coming out of the bleed valve under the light pod. I had a head gasket change 2 years ago, can`t believe its gone again.

Impeller broken off... maybe. I´m going to pull everything off and flush through as much as I can.

[muley]

I would have thought with HGF the coolant would still circulate..

Odd one this..


Jim

[roy666]

Jim - agreed. The coolant should still circulate. I´m getting no discolouration in the water, no sludge or gunk in the oil, dip stick oil clear and good. Do you think possibly if it is HGF that the combustion gases are passing into the water system and preventing the water circulation? I´m getting a bad feeling... HGF again after 2 years.. wierd!!

[muley]

You could try a 'sniffer test' into the header tank to check if exhaust gases are getting into the coolant ~ HGF failure..

Rgds

Jim

[Simon_P]

With a cold engine does it overflow straight away or after some time? How long?

What gives you an indication that coolant isn't flowing? what were you doing to get it to flow?

The surging dropping back surging is just pressure build-up and release, the only sources of pressure are boiling and HGF. (the pump balances itself)

[roy666]

Hi, When the engine is cold it takes a little while and then surges.. after about 5 mins. And the only indication I have that the water is not flowing is the bottom of the radiator, off side, that hose and the rad in that area is cold. I`ll get to do some tests today.. sniffing, etc, and have a better idea of whats going on. But I do feel its a HGF. 2 HGFs in as many years.. WTF!!

[alan e]

Why not do a piston pressure test if it is a blown head gasket the pressure will be lower in one due to pressure leaking pass the head gasket into the water ways.

[Simon_P]

If you have taken the thermostat out and the radiator is still cold after 5 minutes then it sounds like lack of circulation. + read your original post again
Do you mean cold as in the same temperature as when you started?

The pump is fed from the radiator and the heater so a blocked radiator or hose can be bypassed by the turning the heater on - you have tried this and no circulation.

So my guess is that during your spirited driving the cast iron impeller has cracked resulting in it spinning on the shaft.- consistent with the sudden failure you describe after 4 hours of being ok. And is the only non-catastrophic water pump failure I can think of. I'll guess that the head gasket is OK.

Just my guesses!

[lotusflasherman]

its working well .. a week ago. Now a have major issue with the coolant. Drove back from Scotland yesterday, hard drive, lots of high revs, after about 4 hrs non-stop driving the temp went right up pass the ¾ mark .
Water pump on the engine was new on last service 1 month ago when the cam belt was changed.

Just noticed what you wrote so I think Simon is on the right track suggesting water pump failure. Also, I reckon you ran OK for far too long for it to be anything to do with an airlock trapped in the system from the rad change.

Reliability Engineers have the term "Early Infant Mortality Failure" for components that fail just after being put into service, the steep part on the left of 'the classic "bathtub curve" when failures are plotted against time. Statistically if they don't fail early they will continue to work for a long time reliably until failures begin to occur due to bearings wearing out or material fatiguing. (Desire to change components that are in the middle of that reliable period gives rise to the "If it ain't broke, don't fix it' response, statistically a new component is more unreliable than one that has been in use for half it's expected life.)

It seems to me very likely that you've had "Early Infant Mortality Failure" of your water pump ... or in plain English - a duff one was fitted ! There were some problems expressed recently on other threads about Rock Auto supplying pumps that needed modifying before they'd fit properly. Where did yours come from?

I think it quite possible to test the pump before you start pulling anything apart willy-nilly ...

Water circulation: the water pump 'pulls' water from the large radiator hose near the cambelt and pushes it through the block and head towards the thermostat housing, heater take off towards the heater valve and small bore bypass pipe that runs along the block just below the exhaust manifold and provides a flow path for when the thermostat is closed. This will work best with the thermostat closed.

To do the test - close the heater valve, remove the hose from it and add an extension hose to make it slightly higher than the water level in the header tank. (Top up the header tank so you've got normal level and replace the cap if you've lost any). You've now got a cooling system full of water with an open hose at the highest point so stick the hose into something to catch water and start the engine for just a few seconds. If the water pump is OK you should get some water being pumped into your container, if you haven't then the pump has failed and Simon was correct. Not good news but probably better than a head gasket failure ... and if pump was only changed a month ago there shouldn't be any seized bolts..

[roy666]

Thanks Guys.. some great stuff here.. and I do like the idea about "early mortality" Phil. The new pump was fitted by Gerald at GST where Ive been going for years to have the car serviced. He did a cam belt change and noticed the pump was leaking so changed it. I´ve already had a chat with him and he agrees could be a failure of the pump. I´m going to do the test that you suggest. One of my other problems is that my heater control knob has become jammed (been like that for ages, just never got around to freeing up the control lead to the microswitch), so its stuck on hot all the time; not that that should have any impact on this scenario. Thanks for all the advice... keep you posted. M

[Rambo]

But where did you or Gerald get that water pump from Roy ? Phil is correct in thinking that there were problems with some of the Rockauto water pumps. I can't remember which one (Airtex ?) or what the particular problems were (wasn't HJ2 having quite a few water pumps failing ?) but I will try and find the discussion for you

[Rambo]

Here you go Roy, there might be some useful stuff here ?? Pay particular interest to posts from 2017 onwards....

viewtopic.php?f=29&t=19704&hilit=Water+pump+failure&start=20

[Simon_P]

Just for completeness of guessing - I mentioned the cast iron impeller - suggesting that it was the other aftermarket pumps. I prefer the Airtex pump as it has a pressed steel impeller.

[lotusflasherman]

Thanks Guys.. some great stuff here.. and I do like the idea about "early mortality" Phil. The new pump was fitted by Gerald at GST where Ive been going for years to have the car serviced. He did a cam belt change and noticed the pump was leaking so changed it. I´ve already had a chat with him and he agrees could be a failure of the pump. I´m going to do the test that you suggest. One of my other problems is that my heater control knob has become jammed (been like that for ages, just never got around to freeing up the control lead to the microswitch), so its stuck on hot all the time; not that that should have any impact on this scenario. Thanks for all the advice... keep you posted. M

If the heater control valve is jammed open you'll have to modify the test I suggested or water will be coming out of the valve all the time from the direction of the heater. Another end of that Y hose goes to the electric coolant pump (ecp) so you could use that and it's long enough that it won't need extending. You'll have to remove the incoming ecp hose (the T off the long hose than runs just behind the rad) and block it - wine bottle cork might be suitable, and remove the outgoing end that leads to the heater valve and thermostat housing. If you feed it out from under the top hose it should be long enough to get it higher than the header tank. You'll probably loose quite a bit of coolant setting that up but think you said it's virtually water now anyway ... so refill system and proceed as previously suggested...

A very large number of Lotus owners I meet at the TLF Norfolk and TLF Herts/Essex/Cambridge pub meets use Gerald and I've only ever heard praise for his work and business ethics. Consolation for you is the old pump 'was broke and needed fixing' so leaving it wasn't an option. Can't imagine Gerald would fit anything that wasn't right so seems it may be just an unlucky 'early life failure'.

Keep us posted ..

[roy666]

Hi Guys – thanks again for all the insight and advice. I’ve been away for a while so have only just got back to looking at the car. So.. the “Phil” test for the water pump. I took off the inlet hose to the ECP and plugged that hose with a cork; then took off the outlet hose coming to the ECP, which is the ‘Y’ hose from the thermostat housing. So now the ECP is removed from the coolant hose system. I raised the ECP outlet hose above the level of the header tank and turned on the engine: nothing happened. I could see the level of the water inside the ECP outlet hose but no movement at all. I let the engine tick over for a good 2 minutes.. and still nothing.
I hope I got this test right,.. but it does seem like a water pump failure. Now – how to get the water pump off... I’ll have to read up on that one. Thanks again – Phil and chaps.... I’ll let you know what state the water pump is in once I get to it. Mike.

[roy666]

Hi Chaps.. well, bad news. It was the water pump impeller which had somehow failed. It came off the spindle and lodged itself in the water pump housing. Coolant stopped flowing, heat temp went up, I failed to notice it in time, until the engine warning light came on and by then the engine was baking beyond belief. And by that time it was too late and the head gasket failed. I’ll put some pics of the water pump on the site soon and i hope to get some warranty costs back from GST. For those who might be interested, I shopped around to see who could do the HGF the cheapest.... latest labour costs per hr (Ex Vat) from the service centres near me. In the end Jon Saunt (ex-Storm) is doing it for me.
Allon White £75
Lotus Silverstone £82
Castle Sportscars (Stansted) £65
Kelvedon £55
Central Lotus (Notts) £85
GST £58
Jon Saunt £55