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I think mab is right get a 2nd opinion, normally when a head gasket goes between the combustion chamber & water jacket the car will most likely overheat where your temp seems ok & also it will normally over pressurise the system blowing coolant out all the time but you seem to have no pressure in your system
 

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Discussion Starter #62
Hi, no they aren't mini specialists. Its the same garage that did the pressure test for me last month where the car got towed to initially.

No reason not to believe them as they've got a good reputation locally and the guy doing the test today came to reception and showed me the coolant tester thing with the blue / yellow liquid. He said it showed up straight away.

Ive learnt a lot from you guys during this and to be honest, none of the supposed symptoms of a blown HG are present and as you say, a blown HG would normally result in increased system pressure whereas my car is showing minimal or no pressure...

Part of me wants to get a second opinion but i cant afford another diagnosis charge.

Having already shelled out £90 for a tank, £11 for a cap and £25 for a combustion check yesterday.

The fact i spent most of last night looking for a new car probably says a lot about where im at.

I should also mention that i bought this car with a 2yr parts/labour warranty but as usual with these things, they aren't worth the paper they're printed on...
 

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If you have already bought the tank & cap I would fit it & see how it goes
I would agree, if you are thinking of selling up and already have the above parts this could be a cheap fix so worth a try.

A similar case on this Renault forum below started with same symptons and was the cap even though a garage had done the exhaust gas in coolant test and said the head gasket had gone........a fix that cost £4 and not £400+ as a result.

Quote:
"False positives can occur and only a detailed knowledge of the test and pitfalls will highlight these. Often test kits are sold as infallible and only the small print (if any) explain a bit more.
The gas test shows that there are products from exhaust gases in the coolant.
And as far as I know, does a good job of that. What it doesn't do is say how the gasses got there or (again as far as I know) how long they took to build up."
..engines produce a large amount of heat and volume of toxic waste gases and in time they do find a way through somehow to contaminate the oil and coolant
http://www.renaultforums.co.uk/showthread.php?t=254650&page=13
 

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Just a quick up-date from me regarding fitting an additional 'o' ring under the header tank cap.

I have made several long runs since installing the 'o' ring and yes...... it still leaked until I tightened it down a bit more :angry:

It does now appear to be pressure tight and no longer leaking coolant, BUT I did eventually have to tighten it down probably as much as the new cap without the 'o' ring in order to get a good seal.

So on balance I think the BMW caps are still crap, and you appear to need to tighten it down beyond the point where you can easily undo it without the use of a tool.......so routine coolant level checks remain difficult to do especially if you have an alloy tank where you cannot see the level through the side of the tank!
 

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Discussion Starter #66
Alright, lads!

Thanks for the responses since last week and also thanks for the update on the 'o' ring trial.

Its all much appreciated.

Been no change as far as my car goes but thats because the tank STILL hasn't arrived!

Got a new OEM cap waiting to go as well.

Cars been driving normally.

But..... Something came to mind last night which was a little weird.

I've never seen a combustion leak tester before and when the mechanic showed me the results of mine last Friday, i took his word for it. The test he showed me had blue liquid in the bottom chamber and had yellow liquid in the top one.

I thought the tester contained two different types of liquid and as the gasses passed through the lower chamber, the top chamber would indicate if theres a problem.

Having now watched a few you tube clips of people doing these tests, its now clear to me that if there are ANY gases present then BOTH chambers change colour.

This is definitely not what mine showed as!

Possibly the garage trying to take me for a mug?

An old friend of mine is coming round tomorrow with his test kit and a coolant pressure tester to take a look.

After all, how do i know they even did a pressure test last month.

Im really sorry for blabbing on so much but i really do appreciate your advice - all of you!

Thanks
 

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That's who I got my tank from.

I did have a couple of problems fitting it:

1) you need to add a couple of bolts to act as studs to the lower rear bulkhead fixings as on the original plastic tanks these are moulded in. I added some silicon tube on to the bolt threads to provide a tighter rattle free fixing.

2) the angle that the top hose connection is positioned means that the hose runs very close to the power steering tank. Not a major problem, but one that could have been avoided if they had welded the top connector on at a slightly different angle.

All in all an excellent tank that looks just as good as the considerably more expensive Forge talks.
 

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Discussion Starter #69
Hi guys, sorry for the delayed reply. Been in hospital.

My new tank still hasn't arrived so had to cancel and re-order the thing!

Should be here by the weekend they say...

Anyway, my mate did another combustion check and the top chamber turned a slight green but the bottom stayed blue. However, with a few squeezes, the liquid in the top chamber turned back to blue???

We thought his liquid may have expired or something so he said he'll come back again once he bought some fresh stuff and re-tested it on Monday.

On Monday, i took the car to 1320 and they did an engine healthcheck (without dyno) and the leak down test was fine.

He reckons it might have been an air lock so he bled the system at the same time. They reckoned that its sound and to run it for a few days more... He tried to do a coolant pressure test but the pressure wouldn't hold at all yet no leaks showed up so he reckons the seal on his tester was knackered because if it lost pressure at that rate then a leak would be very obvious.

That night, my mate came back to re-test with new liquid.

It stayed blue in both chambers and he thinks its fine, too!

However, I've done what some of you said about taking the cap off and running it up to temp but by car doesn't create a swirl OR bubbles so what does that mean?

The hoses are all warm but they're soft. The hose at the top of the expansion tank wasn't as hot as the others if that helps?

Also, the coolant smells of ammonia - really badly?!?!?!

Apologies for going on but had a lot to explain...
 

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Discussion Starter #70
Hello! Back again. Hope you guys are all well?

Been back in hospital and discharged yesterday so wanted to have a tinker ASAP today.

I wanted to try the idea of running the car up to temp with the rad cap off again (just in case I messed up last time) plus a few other things I did today as part of the process of elimination.

BTW the car has been sat on the driveway for the last 10 days with out moving - got the missus to start it last Thursday, that's all...

1) Took off rad cap to check coolant level - was as before -just over the squiggly lines on the bottom.

2) Used hydrometer to check coolant strength again - all fine.

3) Re-checked 5a blade fuse in engine bay fuse box - perfect.

4) Re-checked 30a blade fuse in engine bay fuse box - perfect.

5) Tested green relays R3 and R4 by swapping them with the headlamp washer relay in the passenger footwell fuse box - both relays made headlamp washers work so I guess they're both ok, too.

6) Checked the two "square" fuses in the engine bay fuse box FL9 (30a) and FL11 (50a) - both seem good.


I wanted to check the above steps to see if my first stage fan kicks in at around 105c (assuming it didn't boil over beforehand as usual)

7) Set OBC to show coolant temp on speedo and started engine (with rad cap still off).

8) Engine was idling perfectly for around 10 mins - temp gauge was in normal halfway position and OBC temp was showing as 72c.

9) Checked coolant bottle and could see that coolant level had raised slightly as it got warmer but still below "MAX" marker on tank. Top hose was warm as were the hoses on the top and bottom of the expansion tank.

10) Increased revs to 2000 rpm to get temperature up - got to 84c when I let it drop back to idle again.

11) Re-checked coolant level and noticed it was now over the "MAX" marker but below the filler neck.

12) Coolant shortly poured out of the expansion tank (not violently or anything BTW) so shut off the engine immediately.

13) OBC display was showing coolant temp at 97c at this point.

14) Engine was off and coolant continued to pour out of the tank for a few moments and after about a minute or so, it began to stop and the level naturally dropped below the filler neck.

15) I cleaned everything up and put the rad cap back on when I could see the coolant level was at a reasonable level - I'll re-check this again tomorrow once cold again and top up if necessary.

Does any of the above seem irregular to you?

I'm probably wrong but it seems that the thermostat works but maybe the radiator could be clogged?

My understanding is that once the engine is up to temperature then the coolant goes from the engine to the thermostat then to the expansion tank. From the expansion tank, it then goes to the radiator via the top hose to cool down and then back to the engine to repeat the cycle?

Although I'm not 100% certain about this, when I noticed the coolant level raising in the expansion tank as the temp went up, I couldn't tell if the coolant level rose via the top or bottom expansion tank hose but it was "calm" the whole time so it makes me think it came via the bottom hose on the expansion tank.

Is that right? If not, would that suggest a blockage at the radiator?

Either way, I didn't get to check my first stage fan again hahaha

BTW - the car has a new expansion tank and rad cap fitted just before I went to hospital so that can be eliminated from the suspect list finally...

Help!!!!
 

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Have you seen the article in Modern MINI mag about replacing the standard coolant with 'waterless' substitute. This has a much lower boiling point than water/coolant mix and I'm wondering if it might be another option to consider down the line when you have got your problems correctly diagnosed and fixed.

Mine is still leaking from the (new) header tank pressure cap but not on every journey. I think mine is still a sealing problem between the cap and the tank......basically its always leaked slightly ever since I got the car but it is a seemingly random occurance and its doesn't loose much coolant so it's more a cosmetic issue for me rather than an overheating problem.

I'm wondering if you still have air in the system.....in the mag article they used compressed air to blow out all the old water-based coolant and then spent a lot of time bleeding the air out of the system when they flushed it and when they finally filled it; not just from the bleed valves but also by loosening the top hose etc.
 

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Hi Hollywood, ok i havent read all 5 pages but i did read the first two. I have had coolant issues with my mini for over 6 years and only last year it was solved. I have a bit of advice to give (and if you''ve already done what ive suggested in previous posts on pages i apologise).

Have you checked all your water pipes or had BMW/local garage check these. Are you 100% sure you don't have a cracked head? Check the oil cap and you'll quickly know where your coolant is going.

Basically after many years with my car the head cracked (my dad actually discovered it as the car was perfectly fine and so was the water, until he checked the oil). The local garage who had been working on the car for many years as "specialists" never found any leaks but BMW instantly found my water pipes were leaking and i had them all replaced, since then no overheating problems whatsoever :) a little water top up every now and then but otherwise 100% ok. I would trust BMW on the matter and book your car in with them they should get it figured out very quickly.

Hope yours gets sorted, best of luck

Oh, i also replaced my expansion tank many years ago and nothing changed.
 
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