This weekend I fitted a new crankshaft oil seal and timing belt kit , I removed the rad for easyer access, today I put it all back together, filled it up with water heaters are blowing cold n overheating when driving so fitted new thermostat n refilled via turbo hose , burped it again still cold heaters n overheating. Re bled again with cap off for a while and did a drive for couple miles all seemed ok n heaters were red hot bye time I got home. Cooled it off for few hours topped up n shot down shops . Cold heaters again an over heating. Rad fans kick in but stay on constantly. I'm assuming it's a air lock but should it be such n *** to get out, rad is quite new fitted by previous owner, any ideas cos it's getting me down now

 

I've found that the header tank cap spring is really weak and poss letting by when I pulled the sticker off the top it was wet underneath. And I have only filled the car with water no antifreeze as yet would that make any difference ??

 

Any ideas

 

water pump gone?

If the cap isn't holding the pressure the boiling point will be lower

 

sounds like to have a air lock matey.take a pipe of the matrix and fill it,fill you rad by the top hose then jack you car up one side. that should clear it.:-)

 

Ok I'll give it a try, I've had over a dozen Scoobys over the years most have had a radiator replaced of a leak issue but I've never had such an issue bleeding before

 

For now filling with water is fine, in fact the cooling system will run more efficiently for now. If you suspect its the cap i would first swap it for a known good one. If thats not the cause make sure you have no air locks and the thermostat is fitted correctly. If the problem is still present check for coolant leaks, correct coolant hose routing and coolant flow (is the water pump working).

 

All was working fine before hand, after first overheat I swapped the thermostat for a new one I had nocking about. There are no leaks , water level is stable. Rad is noon new. I have no reason to suspect pump because had no issues before belt change, as I said I did manage to get it goin this afternoon for a gd half hour drive with some beans also n fans were red hot, cooled off topped up an it's reared it's head up again

 

Seems like there are many bleeding methods everyone swears by but what is the correct method of bleeding

 

I don't think filling the system via the turbo hose is much kop, I did that till water flowed out the header tank the plumbed the pipe back in. Then pulled top rad hose off an managed to get 4 more ltrs via that , so sounds like people repeating crap advise

 

After test driving the vehilce and then letting it cool down for 24 hours is the coolant level low ?

 

I can comment as only reassembled car today and bleading so tomorrow's another day I guess

 

I've just run it up again still overheating , I've found where the matrix pipes come out of the block they are to hot to touch but trace them back to the matrix and both pipes cool off to a Luke warm at the bulkhead, do you think the air lock is in the matrix hence no warm blowers?!?

 

If it helps...

i did a coolant change a couple of weeks ago. After flushing thoroughly, i connected rad hoses and filled until it wouldnt take no more (about 4 litres) then managed to get roughly 0.75 litre into header tank. 0.5 litre into resevior. * roughly 4.5litres so far* started it up, Ran on idle for 5mins and held the revs at 2-2.5k for roughly a minute. *maximum heat, low-mid fan speed.* (be careful it doesnt take long to warm up) i then let it sit for a good hour or so with the header cap off, and again went through rad and header tank etc... in total i managed to squeeze just over 7 litres out of 7.7 total.

after the flush i jacked the front up before filling and did all this with it still up.

Car has been fine ever since, no trouble whatso ever. (have also finished of the remaining litre through the resevior every few days.

It seems you may have an airlock, thats proven to be a bicth to get out may be best to idle over for a few minutes and left to cool before removing caps and leaving for a while to allow the air to rise (it should do it naturally but with no pressure whatsoever in the system it should move more freely.

Barring that may have to revert to square one and possibly use my technique as i know it works. (this is my first scoob, so if at any moment i doubt myself i wont be trying anything)

also where in essex you from? Im a romford lad

 

Cheers for that dan the man ! I'm hockley.
Ok so cooled off header full of water then removed matrix hoses after the first hose there was a big gurgle and all the water disappeared out the header, flushed the matrix an pipes n re fitted. Filled up header. Ran it up and heaters are hot for first time. Fan still stays on constantly . I drove for about 5 miles slowly as soon as I got up to 40/50 mph temp started rising , back off and it returns to normal temp . So parked up at home turned ignition off and pressure obviously builds up. Top hose is hot as he'll bottom hose is warmish , all along the top of rad is hot but bottom half seems cold as.
I've always ruled out rad cos it's nearly new. But when originally removed rad there was alot of rad weld in system still from when he Bodged his old rad up. I'm a bit more happy cos it's making progress. I never let it get to hot cos I no if it goes above half it's not right so it's off straight away, it never spits out of overflow either.

 

Did any suspicious debris come out the matrix ?

 

Yeh quite a bit of orange muck for about 5 secs till water ran clear

 

Left overnight with cap off, and today managed to get another 3/4 ltrs in via top hose, rad and header tank. Drove about for gd hour on and off boost all seems gd and fans are not on constantly, so fingers crossed looking gd. Bloody air locks are a pain in the *** , won't be messing with the coolant system for a while lol.
Cheers for all your advise guys

 

iv had all your faults that you mentioned but i have not played with any of the coolent pipes. just a nice hard drive and now the bloody fan doesnt want to cut out.

 

Air lock.....mate.....fill it cold,run it,once its hot the heaters may not blow hot,turn it off let it cool,top up and take the car for a run again let it cool and top up you may need to squeeze the top hose to completely bleed and attain the required coolant level....