Temp gauge acting funny/possible split hose

[SteveH]

Started the car up today and did my usual fiddling with the stereo waiting for her to warm up, i usually wait 5 mins and get on my way. However, i looked at the temp gauge and it was still reading nothing (gauge not moved) I guessed something had packed up sensor wise and drove to my inlaws about 6 miles away. I must have driven 200yds and the gauge shot up to normal and all seemed fine. A little further down the road driving about 30-40 in 5th i noticed the gauge had gone up to probably 2/3rds temp (highest i've ever seen the gauge go) then go back down to normal. During the drive it did this 4 or 5 times. Drove home and it was still doing the the up and down routine just higher this time.

When i got home i checked the water pipes and they were pressurised, but as its dark i couldn't check water level or anything really. I did take the expansion chamber cap of though and noticed that the pipe that is directed towards the drivers side wing isn't connected to anything? Is that just an overflow?

In the morning i'll check everything.

[SteveH]

I'm wondering if maybe i've got some dodgy wiring to the fans maybe as it was pouring down yesterday and went through some monster puddles?

[SteveH]

So today i checked the hoses and all looked ok, i topped up the water with about 1.5ltr (bare in mind i've not topped it up in about a 14 months). Ran the car for 20 mins, the temp went up just as it would normally and stopped at just under half way as normal. I then gave it 2-3 mins of fast idle and everything seems fine temp wise. However, i noticed that the water is bubbling up through the expansion tank. Not boiling just bubbling.

Any ideas? please don't say headgasket or i think i'll cry.

[The Vee]

If it was that low the bubbles are "probably" just air bleeding out. When cold did you remove the rad cap and fill from there?

[SteveH]

I filled the radiator, then filled the expansion tank both with caps off and when cold.

[The Vee]

OK. There is a bleed bolt just above the thermostat housing for releasing trapped air when you fill. TBH though, as yours sounds like it's doing, they self bleed quite easily without using it. What you need to do now is just keep an eye on things and establish if there is a leak or whatever to cause the loss in the first place.

[SteveH]

Yeah, I'll see how it goes over the next few days. I'll mark the expansion tank after a drive to see if I'm losing water.

[The Vee]

You'll probably find a little loss at first while the air comes out. Don't let the expansion tank empty completely or you run the risk of an air lock between rad and tank. If it does seem excessive, check things like rad cap, weepy hoses, fans working etc etc before delving into the depths of head gaskets and the like. A pressure test wouldn't be a bad idea on the cooling system. The header on the rad is also known to weep on these. Hope it's sorted easily.

[wintertidenz]

Check the little water temp connection just after the top housing where the bleed bolt is. The wire there likes to snap off and screw with the dash readings - I eventually had to solder a new spade bit on the end as it snapped off and I had no temp gauge.

[SteveH]

Update: Everything was fine all week, no big water lose. Saturday morning i notice a wet patch under the car and the water level has dropped down. My wife was the last to drive it and she only uses the foot down everywhere driving technique! so i'm guessing that that bit of extra pressure when the cars driven hard is causing a leak somewhere.....can i find the leak anywhere, can i fork! Not sure how to test to find the leak?? On the plus side at least i can safley assume its not headgasket as the water was on the floor.

[elnevio]

For the sake of a fiver, replace the radiator cap. They can fail, possibly meaning that more coolant goes out to the expansion tank than it should let out, which it then vent out of the overflow pipe to the driver's side wing.

Other popular leak points include the top plastic of the radiator. However, it's not always readily noticeable as the coolant usually evaporates pretty quickly.

Approximately where under the car was the wet patch? Front of engine? Back? Which side?

[SteveH]

After a few weeks trying to suss out the problem with limited time to spend on the car i noticed the water seems to leaking from the water pump :-( Some days its fine and wont leak and some days it just chucks the coolant all over the floor. Looks like i'll have to do some engine surgery then :-(

[John TheAntique]

Before you start major surgery just check it's not normal aircon discharge. If you have had the aircon on there will be water discharged under the front slightly towards the passenger side. Let it idle for a bit with the aircon full on and see what happens.