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Discussion Starter · #1 ·
Hi,

My car had a test done last Friday for combustion gases in the coolant.

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 just assumed 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 the coolant pressure test they supposedly did last month.

Im really sorry for blabbing on so much but i really do appreciate your advice - the test he showed me doesn't quite check out for me... What do you guys think?

Thanks
 

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My tester only has one blue liquid, you draw air out of the expansion tank into chamber 2, and eventually it will filter through to the liquid chamber changing it's colour (or not)
 

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Discussion Starter · #4 ·
Cheers for your replies. Maybe I've confused you.

I think I'm now aware of how the test works but my concern is that the test that he showed me from my car had blue liquid in the bottom chamber yet the top chamber was bright yellow.

If the same fluid is exposed to the same gases then surely both chambers will either both be blue if negative for gas or both yellow if gases are found.

Then how come my "test" both colours???

I just don't get how that would occur because the gas goes through the bottom chamber fluid first so if anything, the bottom chamber should've been yellow and the top one blue if thats any kind of justification hahaha

I hope that clarifies things a little cos this is doing my nut in!
 

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Discussion Starter · #7 ·
Exactly! Thank you!

I think he's trying to mug me off.

Dont get me wrong, i know much about this sort of stuff but glad you all agree its probably a blag...

You tube to the rescue hahahah
 

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Why are you testing coolant? How about telling us whats wrong with your car. Do you have head gasket issue? Cracked head? Or just a dodgy thermostat.
 

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Both chambers started blue both changed colour, I replaced the first chamber so you can see the colour difference maybe the mechanic did this also, replaced the head gasket after having the head checked and all was well


 

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Discussion Starter · #10 ·
Nice one!

I'll explain the reason for asking (don't nod off)

Basically, my R53 overheated in traffic back in January. The temp gauge was in its usual position (halfway) but I've since learnt that these gauges aren't a true indication of coolant temperature.

Anyway, I pulled over literally as soon as I saw steam and could hear the coolant bubbling over. Opened the bonnet and coolant was pissing out of the rad cap.

Not sure exactly how much coolant it lost but the tank was empty so I let it cool a little and topped it off with tap water from a local shop. Drove home perfectly.

Got a coolant pressure test done the day after and that checked out ok but the only thing they couldn't test was the cap itself which suggested that was the fault.

I bought a new OEM cap and fitted it but since then, if the car gets to 95c(ish) according to the hidden "test" menu on the OBC and coolant starts to trickle out of the rad cap.

Sometimes the car can get over 105c and it won't leak and other times it's around 95c and it'll trickle out.

I originally thought I may have over-filled the expansion tank that night (it was pitch black) so figured maybe the car was blowing off excess coolant. I've also been bleeding it but hardly any coolant OR air comes out of the top hose bleeder?

Since then, I've confirmed my first stage fan doesn't work and as soon as I notice the temp hitting 90c I turn the heater to 'HI' on full blast to drop the coolant temp by a few degrees until I get moving out of the traffic again.

The car drives perfectly, starts every time, doesn't smoke and the oil is fine. No evidence of oil in the coolant either!!!

It seems strange but the normal symptoms of a blown HG would be all or some of the above at least but mine looks and drives like a champ.

Also, a blown HG should also increase the pressure in the cooling system yet if anything, my car doesn't seem to have ENOUGH pressure - I can take the rad cap off when it's 95c and I get no hiss or anything?!?!?!?

I know it was foolish to do that but it was to see if it was over-pressurising and I was careful when I did it.

That's what's led me to get the combustion gas check done.

If it makes any odds, the tester used was one with two chambers (one on top of the other as opposed to the one in the picture above)

By the way, your reasoning could be legit - he may well have changed the liquid in the lower chamber to show me the difference although I'm still really hoping he's just blagging me!
 

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Discussion Starter · #11 ·
BTW in my previous post, it was meant to read that I DONT know much about this sort of stuff hahaha

You lot must've been thinking I'm a proper knob (I am a bit)

Any help would be cool!

Thanks
 

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Souds like an air lock in the block and the header tank is getting pressurised and blowing buy the cap. If you remove the cap on the header tank with the engine running can you see the coolant cycling or can you see any bubbles coming up.
 

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Discussion Starter · #13 ·
Hi mate, to be honest i cant remember if I've looked at that.

I think I've had the cap on most of the time apart from when im checking the coolant level.

I can try it tomorrow and report back if you like?

I assume i need to have the car at running temp so is it something i can check when i get to work in the morning?

Just keep the engine running and remove the rad cap?

If i see bubbles, should i be worried etc etc etc...

Cheers!
 

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Remove cap and run car to temp. You should see vortex/swirl in header tank. If no swirl but bubble you have air lock or possible water pump issue. Now ive never had this issue on a mini but my grale had the very same issue many years ago. It had air lock in the block and was a bastard to get out. Many an hour spent pulling hoses off. As to any damaged, it will depend on how you have been driving it or hoonin it about.
but if you have been sensible, you should be ok. It might be worth doing another coolant gas test one the fault is found.
 

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Discussion Starter · #15 ·
Hi mate, sorry for the delayed reply. Been in hospital.

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 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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When was coolant last changed? And what type of coolant is it?.
Does stage one fan come on?
Does thermostat open?

You've had this issue for a while. Did the problem occur after topping up over winter?

I would of expected you to be able to see the coolant flow through the header/expansion tank. Make me think you have something blocking the flow.

If I had to guess, I would say the thermostat is fucked and not opening, allowing the coolant pressure to build up and blow by the header cap.
 

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Discussion Starter · #17 ·
The water pump was supposedly changed just before I bought it in May last year with 76k miles so i assume coolant was changed then too - its now on 85k miles so should still be fine.

Not sure what type of coolant - its blue hahaha

First stage fan doesn't work as far as I know.

With the thermostat, I cant tell really. I now use the OBC temp gauge and it takes about 10 mins of driving to get to 80c. It will typically rise to around 84-86 while cruising and only gets to 90c plus when in stop/start traffic so can't tell if thermostat is working or not? Sorry.

I get heat through the heaters so would that mean if the thermostat is knackered then it must be stuck open rather than closed?

As others have said, my car if anything seems to have too little pressure than too much...
I've never ever smelt coolant like that so no idea what's going on there!
 

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Think it might be worth removing the thermostat and check it out fella. If you constantly boil the coolant it could cause the antifreeze/coolant to break down. Not sure how much hassle it is to remove, I've never had to do one on a mini.
 

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Discussion Starter · #19 ·
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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Watet is not being cycled through this engine. Water is boiling in the block and pushing back up through to the header tank.
pull the hose of the water pump (outlet) and crank the engine. If you get water, the blockage is past this point.
Im afraid you got to start pulling things off
.
Has the water pump rotted its guts out, it can still be turning but not actually pumping anything.
Rad blocked. Etc

I would also suggest sorting out you stage 1 fan if you are going to pull the rad.
 
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