(Home) Coolant loss, thermostat (Sp+)

My 4WD Townace still has a cooling problem. On a recent trip to Eastbourne, about 125 miles away, the outward journey was fine. BUT halfway back in the evening, the temp gauge started to fluctuate about the mid point from half to 3/4. The engine did not overheat but on return I checked the rad, which was full, had to be topped up with 2 litres of water. I have had problems in the past with the cooling which was a leaky Heater matrix whichhas now been by passed. There is no evidence of a leak under the van whilst stationary, the rad cap has been changed, the thermostat appears to be working, there is no signs of a head gasket blown ( no bubbling when rad cap is Off) it may be a small leak in the system, will Rad weld help or has anyone any ideas where to look next?? - (#890) Bob Amabile, 26 Aug 01

Bob, don't mess about, get a pressure test done. There might be a slight leak somewhere. Is the fan coupling OK? Be aware that slight overheating will put quite a bit of water out the expansion hose...
Try radweld, but only one dose, lest thou blockest the rad...
try also checking the torque of all the head bolts.
HTH - (#891) David Miller, 26 Aug 01

The same thing happened to me (93 2.0td) at the end of July, we spent the week in Cornwall but before we left Bristol I did the usual checks. Got down there, all seemed fine and levels still OK. Checked again as we left Cornwall, again levels OK but as we got nearer home the temp gauge went up to 3\4. I very cautiously drove the rest of the way home then checked the water and it needed nearly 3 litres. I checked for leaks and found none. Now at the end of August and it still does`nt need topping up. I can only put it down to driving back with air con on full blast and labouring the engine. Does this sound feasible
Barry - (#892) Barry Powell, 26 Aug 01

Bob,
My symptoms exactly. After a fairly short journey, the temp gauge is almost into the red and I have found the expansion tank full. I have had much advice from BOK members and this has been invaluable. I did all the checks. Viscous fan OK at speed, new rad/filler cap, no leaks anywhere when vehicle stationery. However, I found that the thermostat was very sluggish to open, ie, only opening at almost boiling point
when tested out of the car and, as this is, unusually IMHO, mounted on the return pipe, I feel that there was very little movement of water through the two radiators (4WD Masterace)resulting in so much localised heating/almost boiling around the head & filler area that the expansion pushed unusual amounts of water into the expansion tank, from which it discharged through the overflow. I could find no other route for so much water to disappear and, even after emptying the full contents of the expansion tank, back into the filler neck, more water was needed to bring it up to level. I have now removed the main radiator (no leaks) and flushed this, and the horizontal rad. I do feel that the location of this second radiator does make it difficult to get air out and I have only been satisfied by bleeding from one of the hose connections. Check also, both heaters. They seem to trap a lot of air. There seems to me to be too much turbulence when the rad cap is off so, I am now getting to grips with taking the head off so that I can check all possibilities. Another BOK member mentions completely furred up waterways in the head/block so, apart from the gasket check & change, this will be another area to consider. However, your symptoms are so like mine that I would suggest a thermostat renewal as the next course of action. - (#893) John Davis, 26 Aug 01

In my opinion, the only proof of the system is a pressure test. A sluggish thermostat or scaled up block might cause localised boiling, ejecting some coolant, though. I have to say that I've seen all the symptoms, and cured all the faults- cracked head, leaking rad+ cap, new 'stat etc etc, and even after all that , I seem to use a pint every 500 miles or so, but only in the summer.
Answers on a postcard... - (#896) David Miller, 27 Aug 01

Once again, thanks David, and others, for your imput to solve our problems but, taking up David's "answers on a postcard" invitation can I put forward my own radical theory. Does anyone else think that, on these vehicles, the thermostat has been put in the wrong place ? Who am I to query the integrity of the designers of these splendid vehicles but, IMHO I feel that there are many Townaces/Masteraces being driven around where the thermostat NEVER OPENS. It needs 80c to allow water flow (except minutely from the jiggle valve). As the stat is on the return side of the system, being operated by water which has already been through the radiator (two in the 4WD) and which has lost, say, only 25% of it,s heat, the water, around the head, in my opinion, stays dangerously near, or at, boiling, and seeks an outlet through the pressure cap and into the expansion tank. Has anyone tried an "in line" thermostat on the top hose ? Could anyone put my mind at rest and advise why, on these vehicles, the thermostat is, unusually in my opinion,, fitted in the coolant return line ? - (#897) John Davis, 27 Aug 01

the stat is in the return line yes, but the wax capsule faces the block. When the stat is closed, the circulation around the block will mean that the stat will sense easily enough. We get confused because there's no bypass hose, a la Mini... - (#898) David Miller, 27 Aug 01

Thanks for all the advice chaps, I'll try the 'stat next and at the same time get a pressure test done. I'll kep you posted
Cheers
Bob - (#901) Bob Amabile, 27 Aug 01

My LiteAce is pretty good, temp gauge always stays under 1/2. Recently the radiator light (you know, the one that looks like a Roman temple) came on. I looked under the radiator cap and it looked full to the top. Hm... then I figured it out
The water has to be filled into the white plastic tank under the passenger seat and yes, it needed quite a bit filling up. Am I the only one who was struggling to find out?
Holger - (#907) Holger Laux, 28 Aug 01

Hi, everyone
Good to be back after almost a month away. Had to contribute to this one as it is so close to home. Last february I had the head gasket replaced due to coolant probs. I also replaced the radiator cap about the same time. Since then, being a lazy sod, I've been looking at the expansion bottle as a guide to coolant level and it hasn't budged. On trying to use the heater recently, I found it wouldn't blow warm. Thanks to a nudge in the right direction from Dave, I checked the rad and it needed about a litre of coolant to fill up. So on cooling, the system was drawing in air not water from the expansion bottle and pissing it out when hot. So I have a new cap but it still draws in air. On closer inspection I noticed that the rubber/neoprine seal on the cap is lose and prone to being dragged to one side, hence the leak. I replaced the seal with a home made one from a thicker one made from a "cork-like" gasket material. I now have no leaks bit the cap needs pliers to get it off. A small price to pay. Just returned from a holiday in Scotland and its even improved my poor fuel consumption. If you are experiencing a mystifying leak problem, take another look at your rad cap.
FWIW
Ian - (#911) Ian Dunse, 28 Aug 01

Have just been cathcing up on postings on this site after being away for a while and had a similar problem to this one when travelling back from Scotland recently.
After having to top up rad five times in 300 miles I thought about time to find a leak,after scrawling about for an hour finally found my leak was coming from a metal pipe which comes out of the block right behind the injection pump and travels across the block to disappear round the back just above the starter motor.A small rubber hose is halfway along splitting the pipe into two.
Take a close look at this pipe when hot and under pressure as it is very difficult to see the actual pipe,but under pressure you should be able to hear any leaks.
Fixed my problem by replacing the rubber hose with a longer piece of hose which covered the hole in the pipe. - (#1033) Peter Bennett, 9 Sep 01

I've got a 1990 Spacecruiser (2 litre manual) that's overheating. After 3 to
4 miles, the engine overheats, pressure escapes into the expansion tank,
forcing water out of the expansion tank and leaving a trail behind me.
I've already replaced the thermostat, but this had no effect on the problem.
I don't seem to be leaking water and I don't think I've got a leak into the
oil or the cylinders. The fan is working. If I turn on the front and rear
heaters, the water temperature stays lower and I don't have a problem. I
don't then have a hot spacecruiser, just very hot passengers.
Looking at the hoses (or squeezing them) reveals they are coated on the
inside with what is probably limescale. I suspect therefore, that the
radiator is blocked with scale. Does this seem reasonable to anyone out
there, or is there another possible reason for the overheating?
I'm part way taking out the rad so I can flush it properly, but this
involves removing half of the inside of the car. I'll flush the radiator
several times to get rid of all the gunge I can. I'm thinking of using a
proprietary lime scale remover (e.g. the sort used for descaling kettles
etc) - any views anyone?. I'll also flush the engine block with a hose while
the rad is out.
Do the proprietary radiator flushing products work, is one of these products
likely to remove any blockages? If so, I'll use one after I've re-installed
the radiator.
I'd appreciate all the help I can get on this. I need to take a 200 mile
round trip on Saturday to see my eldest son off to University. I'd rather
have this sorted out by then.
TIA
Neil - (#1140) Neil Hall, 27 Sep 01

Have a C reg space cruiser and having problems with cooling. After long journeys (sometimes not so long)water boils up and overflows through the expension tank. Changed pressure cap and thermostat. Loss of water and no sign of a leakage. Checked everywhere possible including the head gasket. Any suggestions?
- (#1232) John Boneham, 13 Oct 01