My HiJet Overheating problem - Solved...

Hi guys, long time jet owner / forum watcher but ive not posted before.

I had the dreaded overheating problem in my 2001 1.3, and I managed to fix it after reading tips on this forum. Just wanted to say thanks and share my experience in case it helps others...

My symptoms included ;

Sometimes - not always - the temp needle zoomed all the way to the right "HOT", coming down a bit when driving faster in the cool air, but stop for a minute and it would shoot up again.

Gurgling pipes, expansion tank / overflow pipes hissing, coolant loss.

Cold bottom radiator hose.

No heat from heater.

My fix / experience:

Couldnt see any sign of actual leaky pipes or head gasket failure.

So cheapest option next. I replaced the thermostat (which is directly under the handbrake) with an £8 fleabay one. The rear engine cover had to come off (about 10 bolts), seats came out (2 bolts each), seatbelt fixings (1 big bolt each), along with the handbrake (a few screws and a few more smaller bolts).

I drained the coolant by removing the little white plastic plug which is down near the rad under the front. The fluid which came out was perfectly clean - so no flushing needed.

Thermostat housing "bolt 3" was worrying me as a lot of people reported it being hard to get to - but it turned out to be quite easy. I used a regular 12V hand drill, which comes with an extra long 6" thin screwdriver type socket attachment, to which I attached one of the 10mm sockets which came in the drill case. Because the extension was so thin, it reached right in there and undid it fast..

Thermostat housing came off easy, and the thermostat itself came out with a bit of a tug with some stilson grips.

Remember to visualise (or take a photo) of where the small "pin" in the actual thermo unit is before you take the old one out - the new one has to go back in exactly the same way.

I removed the front bumper / valance by mistake - you dont need to (although it does make crawling underneath a bit easier) - the top-up for the rad is under a cover which just pulls down from the top - its on a hinge (I didnt know that after 10 years owning it!)

Both my rad caps were fine - not perished at all so didnt replace those, just gave them a bit of a clean.

After putting the whit plug back in, and refilling the coolant (about 4 litres total fluid I think), and letting it heat up as recommended, the extra rad fan wasnt kicking in - people on the forum here have been saying that to test the fan works, you put some wire between the pins - but which pins? which connector? There were 3 that I could see.....

I discovered that on my '01, 1.3, I have a coolant sensor which is installed (screwed in) inside one of the lower fat pipes - its about the shape and size of a spark plug. You can just see it down under the expansion bottle, under the passenger seat, hidden behind a bit of corrugated cable protector stuff. The electrical connector on the top of it was a bugger to get off so some reason - I had to take it off from underneath using a screwdriver to squeeze the clip open, and a pair of grips to pull it off. Once off I connected a 3" piece of insulated wire, stripped at both ends across the pins of the plug I had just removed, and hey presto the fan kicked right in.

So the problem is not the fan, the fan motor, or electric not getting there.. It has to be the sensor which is bad - or is it.....?! I will explain more in a moment.

People have been talking about all sorts of procedures for bleeding the coolant system, but all I did was fill it up from the front filler hole until coolant came up out of the filler cap under the passenger seat. I re-fitted the passenger seat cap. I filled it up some more from the front. I got under the front of the van and squeezed the bottom rad hose 9 or 10 times to purge the air, topped up some more, checked the expansion tank and job done.

So was my coolant sensor bad? NO. It just wasnt working because there wasnt enough coolant in the pipe it is installed in. Once topped up, air removed, its working fine.

I was lucky I guess. Im my case I had no blown head gasket, and no leaking pipes - which of course you should check for also :0)

Well thats my overheating problem sorted. And it only took about an hour and a half.

hth someone...

thanks guys.

Nice write up.

How many miles have you done in it since?

About 100 or so miles. All slow driving.

The temp gauge seems to be back to where it has been forever - just under 1/2 way.. Fingers crossed its fixed for good.

The last one I fixed did about 600 mile sweet, then it got thrashed around the peak district and overheated big time. Stripped it all down to find the head gasket popped again and a little hose clip had been leaking. That ones now done a few thousand miles trouble free.... So far anyway!