Exploding coolant hoses??? Read on

[Dom B]

Ok this one is a bit of a question and later hopefully answer post.

For a few months I have been bursting various coolant hoses from the little turbo returns to the top hose with a massive 8inch gash and I blew the top off the radiator. The top hose burst on my way to the doctors with a broken rib, I had to patch it up, carry on to the doctors in agony then after being told to go straight to A&E as they thought it may have been pneumonia at the time before the xray showed it was a broken rib, I had to borrow water containers from the doctors to fill the car up to get it home, fun and games. The car also lost its water in rush hour on the M25 which was nice joining the AA on the roadside and being charger £200 for the privilege.

Anyway back to the point, I have heard a lot of people saying when one hose goes the others are shortly to follow so I replaced all of them.

The car has always spat out excess coolant and bubbled the overflow tank a lot but i thought this may be normal.

I also saw a lot of folks saying must be head gasket etc so I did all the leakdown/compression tests etc and it all checked out ok. One hose actually burst 10 minutes after parking as I walked past the car, I guess due to heat soak so leaking head gasket would have not affected that at all.

Trying to search for the problem I decided that a coolant swirl pot was a possible cure to remove the gas pressure more effectively. Most turbo cars need them and a lot get them from the factory as standard. Not seen many people here talking about swirl pots on VR4 engines. I will make a write up shortly about making the pot.

So I installed the pot and ran the car up. The vents were from rad top tank and one from each turbo return as these are the locations of most bubbling possibility from local boiling. I noticed there was no water coming from the turbos. Odd I thought. I took the hoses off and blasted compressed air back down them, the front turbo blasted out a bunch of bubbles after an initial blockage. The rear turbo however is totally blocked to the compressed air so I assume the pipe of housing is blocked too, for how long I have no idea.

I now think the hose issue was caused by this, either causing a pressure buildup down a narow pipe hat cannot release it quickly enough of if the turbo is hot and some water gets through it may immediately turn to steam and bang goes a pipe like throwing water on sauna rocks!

I need to remove pipes and possibily turbo to check this all out, so I will keep you informed of my findings.

Nick I remember you had a similar problem.

The question part, has anyone else had problems with blockages?

The coolant was full of a lot of brown dry crap that I had to go to town on flushing and 2 bio cleaners to get rid of it but the blockage has already been done. looks like th crap that forms when 2 coolant types mix. The car was like it when I got it, definately not oil in coolant.

[Louis]

Quote:
The coolant was full of a lot of brown dry crap that I had to go to town on flushing and 2 bio cleaners to get rid of it but the blockage has already been done. looks like th crap that forms when 2 coolant types mix.

Sounds exactly like the mixing of 2 different coolants. I had this a while back, had car serviced ans they topped up antifreeze, about 5 weeks later i noticed bubbling when car stopped, 2. weeks later burst water hose( smsll one on thermostat housing) loads of muddy brown water. Repaired it, a week later, another hose burst. So i checkef around and the "mixing antifreeze was mentioned". Very soon after that the rear head gasket went, internall heads and block fine, but gadket went between piston and water jacket.
To see If head gssket has gone, when car is cold take off rad cap, car stationary, run engine and rev if water surges when engine is reved then there is a problem, you will see water surge out of top of radiator.
If head ok, you will have to flysh with hot water and chemical, and remove all traces of sludge, pain in the arse, but save able.

[exevoowner]

Have seen this happen on a v6 mondao that i had a few years ago and that turned out the garage that serviced before we brought the car did the same thing mixed coolant and blocked the pathways in the heads and waterpump was a pain till the cause was found and 2 days to sort with flushing and changing hoses and waterpump and rad

[Dom B]

Well I have changes all coolant hoses, dissolved the gunk out of the matrix when I had it out of the car and chanegd the radiator. I flushed it 36 times which took around 2 days and put 2 bio flushes through it, an acid flush and another degreaser flush each bring out loads of gunk. I then set the car up on an intravenous arrangement with mains water in to the car via a hose and a dump out, while the car was running I purged the water every 10 mins for a couple of hours until it ran clear. It seems the jamming up that happened before I owned the car is still there despite virtually all the brown crud now gone. Problem is where it the blockage. What is stopping the rear turbo particularly getting water.

I have bought a couple of head gaskets anyway, not because they are damaged but because it seems the only way to remove the blockages in the head and block properly, core plugs out etc.

Going to take off the turbo return thin pipe today to investigate.

Can anyone shed a little light on how the coolant circuit to feed the turbos is arranged by way of a diagram? I can see the coolant returns but the feeds are hidden. One looks like it bolts onto the rear of the block but until i remove a whole lot of stuff I won't be able to see clearly.

Will keep you posted with pics hopefully.

[Nick Mann]

If you can wait until tuesday, I can get some photos for you. IIRC the water pipes are the 3 and 9 o'clock pipes, the oil is 12 and 6. The oil drain at the bottom returns into the block, I can't remember where the water pipe goes. I'm pretty sure the water input comes from the manifold arrangement near the thermostat, but not sure enough to state it as fact. How about removing the banjo bolt at the rear of the turbo and running the car for a few seconds. If water throws itself out of the tub/pipe then you at least know the feed is good?

[Dom B]

Looking at the car better, it looks like I made a mistake with the direction of flow, you are quite right Nick the feed into the turbos are the banjos furthest away from the engine block and the returns are the ones closer to the block. I have swapped the front swirl pot hoses to get the flow correct but doesn't look like I can take a swirl pot vent from the rear turbo until I can fabricate a custom hose between the turbo and the engine block. basicially seal off the block port and make a new hose with banjo from the rear turbo to the swirl pot.

Anyway in the mean time the blockage still remains, working on it at the moment. Tuesday is fine I have a few jobs I need to do on the car so it is offthe road for a couple of days while I get them all done. Thanks for the help.

[Dom B]

Found it. I have correctly routed the coolant hoses for pressure bleed and I found the blockage to the reat turbo. Bit tricky but managed to take the coolant pipes off and check them. The ont from the rear turbo to the block was jammed. The banjo bolt was blocked with what looked like a piece of dry silicon sealant that came loose, lodged in the bolt then a load of that brown crud packed in behind it blocking the whole pipe. Water must have been steaming and dropping back down the outlet pipe for ages a bit like a Geyser causing huge sudden pressure variations. I guess that is why all the hoses were blowing. All clear now and all hoses new and I now have a swirl ot to boot.

Vheck out the blocked banjo, anyone blowing hoses I would check this as it is so easy to be a blockage point.

IMG_3926.jpg

Pretty sure banjo bolts normally have holes in the middle!!

[exevoowner]

uselly down the centre and 2 at the top for flow pmsl

[Dom B]

It's a bit of a bitch to get to that rear pipe so I guess they rarely get checked on VR4s

[wintertidenz]

I've had that rear turbo pipe go before - it developed a leak while driving.

It was quite badly corroded inside as well - I've checked the new one semi-regularly since.