continued cooling problems

[popeckia]

Hi,

I posted on the temporary board about my problems with overheating. Unfortunately I still have issues.

I first noticed the problem when the needle was rising higher than normal under typical driving conditions (i.e. not stuck in traffic and not a fan related issue really) and upon inspection, found out I was pretty much out of coolant.

I topped it up, and couldn't notice any obvious leaking and so carried on as before.

The problem seemed a bit better, but soon I was facing the same issues and the coolant level was again low. Upon advice, I checked for any evidence of water coming out of the exhaust but could find none (and still no obvious leaking from under the car).

So, today I replaced the thermostat ... checked that the new one was working fine by sticking it in some boiling water, and all was ok. Put everything back together, topped up the coolant and went for a drive to test things out.... it was pretty quickly apparent that there was still a problem as the needle moved quickly past the quarter way mark that it used to settle at when the car was moving.

It seemed to settle around the half way mark, no fans cutting in at any point. I decided that maybe it was the new thermostat cutting in at a higher temperature, so I pulled over to let the car heat up and check the fans would cut in eventually.

As I sat idling outside the house, the gauge never really went past half way and after a short while I figured this can't be right. So I killed the engine, went and popped the bonnet.... hissing sound of steam coming out of somewhere although not billowing out in dramatic fashion. Went back to check the temp gauge, still at half way. Came back to the front of the car, water all over the floor from under the engine which would seem to be coolant (didn't fancy looking in the tank at this point to check). Don't specifically know where it came from other than under the engine.

In addition to all this, the heater hasn't really been producing any hot air even when the engine is very hot. I assume this is connected in some way. When adjusting the temperature gauge, you can hear it is working and vents are opening/closing but the air temperature doesn't really change in any great way.

Can anyone suggest what to do next please?

[runix3]

Hmmm...some simple stuff to do. Pull the plugs and check for a coolant smell. Also, use a flashlight and look down into the cylinders to see any traces of coolant. I'm assuming you have the 4XE1-WT motor like I do, the normal range the temp gauge sits at is a little below half way. This is using the standard thermostat and not a low temp one. Also, check the cooling lines that go to the turbo and back. They have some small rubber lines that tend to swell up and start leaking after a while. Hope that gets you started.
Alex

[popeckia]

Thanks for the suggestions.

I checked the rubber lines and they don't appear to be leaking (and certainly not flooding out in a way that would explain what happened yesterday).

I'll try and check the plugs later and see if I can smell anything. Is there nothing more directly related to the cooling system that it could be? I assume I am checking the cylinders and plugs in case there is a head gasket type problem?

[Rob-C]

A blown head gasket can cause the coolant to be forced out of the reservoir through the valve in the cap.

[Dave M]

Have someone perform a leakdown test on your cylinders. Do not trust a compression test as that may or may not uncover a head gasket problem. I had a similar issue, gauge rose abnormally in normal driving, lost coolant without any sight of it in the oil or exhaust, etc. Ended up being a head gasket. One thing I did notice in the end was even after letting the car cool, when I removed the coolant tank cap, I could hear pressure being released. Sorry! Hope it does turn out to be something else!

[popeckia]

Thanks for all the help... looks very much like it's something much less damaging. I feel kind of stupid about it (as ever) but having taken out pretty much all the pipes to inspect them, it would appear that I have just been losing coolant through a leak. The leak though (in my defence) was from a crack in the neck of the header tank so it was pretty hard to spot.

I have slapped some sealant all over the crack for now as I need to drive the car tomorrow, but will be ordering a new tank asap. When I took the car to my local lotus mechanic (Lyte and Wakefield in Enfield - very helpful and friendly) he suggested that given the loss of coolant, the gauges couldn't really be relied upon which would seem to explain the other strange symptoms I had.

I guess I'll find out tomorrow once the sealant has dried properly and I re-fit the tank, whether or not this is the only problem - but thanks to everyone for their experience and suggestions. Will report back either way.