To pull head or not to pull head
Submitted: Friday, Feb 16, 2007 at 20:02
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42387
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GQ_TUFF
Ok Some of you would be familiar with this ongoing problem of
mine, of my 2.8 GU spitting its coolant out of the overflow. I have had it at the mechanics last week and he admits there is a problem but he is not 100% sure if its a gasket or head as there is no bubbles when you rev it ect, and he says as the 2.8 runs 21-1 compression you would be pretty sure if you had done the head ect. Now this posses some questions.....I have being told by two sources that their cars displayed the same symptoms and that their problem was the water pump under certain loads actually sucked air in. I told this to a radiator guy and his responses was "bulldust" in 30 years never heard of that one and your friends must be lying....more confusion!!!!.......As you can imaging I want to be 110% sure that its the gasket or head before I commit to this job.
So this is what it does
After a run above 100 km/h about 2800 rpm it starts pushing the coolant across, to the point of filling the overflow and then some, after about 200 kms I have lost 2-2.5 litres.
It won't recover what it pushes over, mechanic reckons it pressure tested normal cold and warm. (yes has a new quality cap)
But around town ie: nothing over 80 km/h no issue, run for 1000 kms and not use a drop???
It isn't showing any oil and water mix and no moisture in the exhaust or rough running when cold or hot.
It has no external leaks that I can find and trust me I have looked and looked.
I have being told by several mechanics that there is no
test for exhaust gas in coolant for a diesel???? I am sure I have heard it mentioned here before.
So please any opinions would be great, or anybody know of some tests that can be done to help the problem be found correctly?
I am putting it on a dyno tomorrow to see if we can see whats happening as it happens as opposed to when it has happened. Apart from that I am stuffed if I know
Any help will be greatly appreciated
Cheers Stefan
Reply By: Gob & Denny - Friday, Feb 16, 2007 at 20:11
Friday, Feb 16, 2007 at 20:11
how long has the cap been on longer than the problem or the same time
it almost sound like the cap going on what you say
steve
is it the right cap to let it suck back ??
AnswerID:
222160
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 20:20
Friday, Feb 16, 2007 at 20:20
Cheers for that, yes 0.9 bar cap....fitted after problem arose.....must add it was not a sudden arrival of the problem more a gradual thing over the last 17000 kms, so thats why I think if it was the big one surly it would not hold on that long
Stefan
FollowupID:
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Follow Up By: On Patrol - Friday, Feb 16, 2007 at 20:24
Friday, Feb 16, 2007 at 20:24
Steve,
I think your right, in as much as air is being sucked in and not coolant. But where???
On Patrol
FollowupID:
482974
Reply By: On Patrol - Friday, Feb 16, 2007 at 20:22
Friday, Feb 16, 2007 at 20:22
As discussed on the phone Stefan, my money is on the water pump seal, allowing air in when cooling and preventing coolant to suck back into the system.
Others will / may disagree but thats OK, you will get a range of ideas presented.
Good luck with the Dyno tests tomorrow.
On Patrol
AnswerID:
222165
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 20:29
Friday, Feb 16, 2007 at 20:29
Well, Its $100 for a pump, and $3500-$4000 to do The top end....I'll give you one guess which I will try first!! If the dyno
test leads me to the smaller one....Whats your garage space doing tomorrow???? LOL
FollowupID:
482977
Follow Up By: On Patrol - Friday, Feb 16, 2007 at 20:36
Friday, Feb 16, 2007 at 20:36
It would have to be the car port Stefan, youve seen my garage!!!!
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482982
Follow Up By: Member - DOZER- Friday, Feb 16, 2007 at 20:40
Friday, Feb 16, 2007 at 20:40
Question...is your 2.8 alloy headed?? Either way, u can try this first if you like.....try tightening down the head bolts, by backing off a quarter turn one at a time then retensioning. Make sure the motor is comd and the rad cap is off/system depressurised,
The water pump does not explain the water being forced out of the system when running....for this to happen, something pretty powerful is forcing air into the system...yes, i think you need to renew the head gasket. It holds back 2500psi at cranking speeds, all it takes is a bit of hard work to get things nice and hot, and to allow a bit of compression past the gasket into the water gallery (remember, at 100km/hr you have a turbo forcing in the air at full boost b4 it gets compressed, so this is where the most pressure and heat is seen in the cylinders....) which are right next to the water galleries.....)
Id be driving round with the cap on the first notch to let the compression out b4 u blow a hose....top it up each morning, run the water level juast above the core.
Andrew
FollowupID:
482984
Follow Up By: On Patrol - Friday, Feb 16, 2007 at 20:50
Friday, Feb 16, 2007 at 20:50
G'day Dozer
Your theory is sound mate, but how do you explain the water not sucking back into the system at cool down, it just remains there. Would the head gasket cause that???
This is a puzzle in its self as to why the coolant will not return to the system at cool down, could there be a residual counter pressure of air when cool?
On Patrol.
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Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 21:35
Friday, Feb 16, 2007 at 21:35
Thanks for that Dozer, Funny about your theroy of letting some pressure out, today I ran a little
test....after it let out around 2 LT, it seemed to almost stop doing it???? It has a 12.7 LT capacity so it was running at around 87% capacity and it sucked coolant back from the overflow bottle to around the MAX fill line. Its like things sort of equalised. As I have being topping up at every possible time, is it possible to over fill the system? I have being filling up the radiator and header tank to the very top and the overflow to the MIN mark.
Cheers Stefan
FollowupID:
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Follow Up By: Member - DOZER- Friday, Feb 16, 2007 at 23:20
Friday, Feb 16, 2007 at 23:20
The system is supposed to work by firstly, having no air in it, secondly letting water out past the cap when it expands due to heat, (and still maintain 0.9 bar in the system) and when it cools, the vacuum caused by contracting water as it cools down sucks it back in via the cap. When pressurised air is introduced, it pumps out the water, leaves air in the top tank, and when the water cools, there is not enough suction to overcome the air space left in the top tank and suck the water back. Andrew
FollowupID:
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Follow Up By: Member - Davoe (Nullagine) - Saturday, Feb 17, 2007 at 15:35
Saturday, Feb 17, 2007 at 15:35
Unless i m mistaken 2.8s are renowned for cracking heads. Alot of the Brunswick v8s are in former 2.8s for this reason. By all means look for a cheap fix but experience has shownme if it looks like dog bleep e and smells like dog bleep e then....................Is probably dog bleep e
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Follow Up By: Danny & June - Saturday, Feb 17, 2007 at 17:59
Saturday, Feb 17, 2007 at 17:59
Try the Thermostat
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Reply By: Member - Davoe (Nullagine) - Friday, Feb 16, 2007 at 20:29
Friday, Feb 16, 2007 at 20:29
Had EXACTKLY the same problem with my valiant gottold more bulldust than whatever ha cracks in head stitched chemiweld everything. ended up cooking the motor and getting it totally rebuilt problem was still there they ended up putting pressurised expansion tank in it which helped but didnt fix the problem. If I evr see those syptoms again the vehicle will be straight in the trader no one knew or could fix the problem. Sel it now i wish I had, caused me years of grief
AnswerID:
222169
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 20:32
Friday, Feb 16, 2007 at 20:32
AAAAAAAAAHHHHHHHHHHHHHH dont tell me that!! lol.....I really hope it is not one of those things, cause I aint gunna do the top end on the off chance thats for sure!!
Cheers
Stefan
FollowupID:
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Follow Up By: On Patrol - Friday, Feb 16, 2007 at 20:35
Friday, Feb 16, 2007 at 20:35
Hey Stefan you didnt need that one mate LOL, dont ask me for directions to
the GAP.
FollowupID:
482979
Reply By: mrbasilbrush - Friday, Feb 16, 2007 at 21:07
Friday, Feb 16, 2007 at 21:07
It is obviously overheating to let out so much coolant.
1 -
check the thermostat is opening properly (boil it up on the stove see if it opens fully).
I had a similar problem in my 2.8d hilux.
It Was always getting too hot and popping holes everywhere in the radiator.
I Was forever getting holes repaired in top and bottom tanks.
Finally decided to just get a new radiator. Then had no trouble.
My best guess is the core was becoming clogged up over the years and the water could not flow through it freely making it overheat.
But when I used to get it repaired I never asked them to clean the cores out.
I just told them to fix the leak only.
Live and learn.
cheers.
AnswerID:
222184
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 21:40
Friday, Feb 16, 2007 at 21:40
Thanks for that, It has a new radiator as it was getting warm, old one was 80% blocked. Now will run up the steepest hills with a load, aircon on and 38 deg heat and not budge the temp.
My problem is air in system only at high load situations, and not recovering what it loses into over flow tank. Has been pressure tested cold and warm and it showed up fine. So back to the possible head gasket or head issue
Cheers Stefan
FollowupID:
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Follow Up By: mrbasilbrush - Saturday, Feb 17, 2007 at 11:29
Saturday, Feb 17, 2007 at 11:29
GQ, Just a thought, If it was the head gasket would`nt that show up in the pressure
test ?
Cheers
FollowupID:
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Reply By: samsgoneagain - Friday, Feb 16, 2007 at 21:10
Friday, Feb 16, 2007 at 21:10
remember ye olde holden 186 engine when you took the thermostat out the coolant took the easiest path and didnt cool the rear cylinders. maybe that is what happend or is whats happening to your system . thermostat may need replacing or at worst , head maybe damaged at the rear cylinders.
AnswerID:
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Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 21:43
Friday, Feb 16, 2007 at 21:43
I will be honest it has thermo housing only to regulate flow but no guts as I removed it.....but it was showing symptoms before I did this
Stefan
FollowupID:
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Reply By: Member - andrew B (Kununurra) - Friday, Feb 16, 2007 at 21:17
Friday, Feb 16, 2007 at 21:17
Gday Stefan
Funnily (not) enough I am in exactly the same position......chemiweld seems to have done the trick, but I have noticed a few bubbles here and there...I'll know a little more on the next run to work.
Mine got a negative
test for CO2 - so the bubbles weren't exhaust gas......I can't see how the waterpump could draw air in at over 9psi (radiator cap pressure). I think the turbo is watercoled....I think these little engines run about 12 psi, so a suspect seal in the turbo could theoretically put 3 psi into the coolant (if all the planets are in line etc.....) I, like you, am at a bit of a loss as to what the problem is, I will probably look at the water pump first, doesn't hurt to change them now and then anyway - the last one I did was about halfway between the Berkley Roadhouse and Cammoweel on a stinkin hot december afternoon, but thats another story! I may consider another chemiweld dose, and re - torquing the head, but it won't be comeing off in my case.....
I have made my decision......when this one requires substantial money to be spent on either motor, gearbox, or even clutch, its Brunswicks here I come! (I can't handle Roachie and Bilbo having all the fun! I don't do that many k's anyway, so this may very
well be the car to see me through the nest 20 years.......just do it "a piece from here and a piece from there"!
Good luck with your 2.8 adventures...pity we both have the same problem or I may have some parts for you....
Cheers Andrew
AnswerID:
222189
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 21:55
Friday, Feb 16, 2007 at 21:55
G'day again Mate, we always chat about the crap things!!! lol
I have being told they have single use head bolts so its off with the old and in with the new,
Well RE water pump....its at 130000kms and still the original so for $100 why not??
Will have a look re water cooling the turbo, I havent considered that.
At what Stage does your low coolant alarm go off? As I mention in an earlier reply after it has lost no more than 2 LT.....It seems to settle down.....but is 2 LT danger zone?
I am really hoping to find out on the dyno tomorrow what is happening at high load, Plan to run it at 130 km/h for at least 1/2 an hour and see what happens.
will keep you posted, why is it you can get the gas (co2)
test where all the mechanics here reckon they cant do it on diesels???
Fingers crossed!!!
I would love to do the chev thing, but I would have to get divorced first I reckon, sold my soul to get this car would have no chance of convincing SWMBO that another 25k is a good idea!!!
Cheers Stefan
FollowupID:
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Follow Up By: Member - andrew B (Kununurra) - Friday, Feb 16, 2007 at 22:11
Friday, Feb 16, 2007 at 22:11
Its all good isn't it.....Last time I had a head problem I witnessed the
test - the water in the
test kit (its a bit like a hydrometer) went
bright green, indicating CO2, a few squeezes in the open air (oxygenated) the liquid went clear. It was repeated in front of my eyes, so it can work. This time, no co2 (performed by the same mechanic). The mechanics may be eluding to the possibility of a diesel squeezing the gas into the water prior to ignition, with the diesels higher compression ratio, but I doub tthis would be the case. It will be interesting to hear about your dyno results...
mine went from 84 to 96 kw with the gas, but to have an accurae comparison the;y would have to be done on the same dyno strait after one another.
There won't be a divorce over the V8, if and when it comes about....I get away with a fair bit really. I compare that with a $50K changeover to the last run out of the real 4wds and I can have a win...sort of. These 2.8 problems would be OK if they were a simple motor with cheap(ish) parts, but everything costs thousands. I liked my old MQ, even though SD 33 parts wern't exactly cheap, there was a few available from wreckers etc fairly cheap and simple to fit (new engine in a day)
Look forward to your results tomorrow.
Cheers Andrew
FollowupID:
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Follow Up By: Member - andrew B (Kununurra) - Friday, Feb 16, 2007 at 22:18
Friday, Feb 16, 2007 at 22:18
Forgot to add, my coolant sensor is a bolt that is about 35 mmlong through the radiator cap (on the radiator, not the plastic tank above the overflow), so as son as that level drops about 35 ml, it beeps away, which is usually about 2 litres or so to add. I am very reluctant to let it get lower than this, as I have heard somewhere that these engines crack heads and do head gaskets if you give them half a chance.lol......sort of.....the $150 odd I spent on this little sensor is great piece of mind, and I will never own a 4wd without one now.
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Follow Up By: GQ_TUFF - Saturday, Feb 17, 2007 at 17:06
Saturday, Feb 17, 2007 at 17:06
your new car!!!
post 42395......worth a look
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Reply By: mazbravo - Friday, Feb 16, 2007 at 21:48
Friday, Feb 16, 2007 at 21:48
had a similar problem with a 4 litre ford it would run hot around town pushing 2-3 litres of coolant out at a time but driving at 100kmh it was fine it had heaps of air pushing the coolant out anyway the problem was the water pump i;e the propellers were all bent back at about 45 degrees and the metal plate between the pump housing and the propellers had broken away which in turn bent them back.
AnswerID:
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Reply By: Red One - Friday, Feb 16, 2007 at 22:25
Friday, Feb 16, 2007 at 22:25
Mate,
Check your oil. If it's emulsified then it's the head. Otherwise happy days.
Cheers
or it could be egg in the system seen it before
AnswerID:
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Follow Up By: Member - andrew B (Kununurra) - Friday, Feb 16, 2007 at 22:34
Friday, Feb 16, 2007 at 22:34
I wish this was always true, but I've cracked a head, and done 2 head gaskets on diesels and in all cases the fault/crack was from combustion chamber to water jacket, an in my cases, it would let gas out under combustion pressure, but not let water back in to contaminate the oil........not a bad thing i suppose, it at least meant that the contaminated oil didn't lead to scored bores and bearings etc....
Cheers Andrew
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Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 23:07
Friday, Feb 16, 2007 at 23:07
oil is fine, and have being told if its a gasket and my car running 22-1 comp...I would have blown it to peices by now. has had symptoms for 17000kms!!!
Cheers Stefan
FollowupID:
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Reply By: mattie - Friday, Feb 16, 2007 at 22:33
Friday, Feb 16, 2007 at 22:33
not sure if someone has mentioned it or not but have u considered that u may have an air lock in the coolant system somewhere that when it warms up it expands and pushes water out and then when it cools the airlock does not drag the water back again, some vehicles have a bleed screw in the cooling system to let trapped air out,
Mattie
AnswerID:
222205
Follow Up By: GQ_TUFF - Friday, Feb 16, 2007 at 23:00
Friday, Feb 16, 2007 at 23:00
yeah this has being mentioned to me off this site, but I dont know of any bleed screw on this engine, maybe some of the spanner boys would know??? Please anything!!! LOL
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Follow Up By: kiwicol - Saturday, Feb 17, 2007 at 11:41
Saturday, Feb 17, 2007 at 11:41
the bleed screw is in the top radiator hose going to top of radiator the hose is in two pieces with a joiner undo
the nut on that careful as it is only plastic and fragile from time Col
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Follow Up By: Member - andrew B (Kununurra) - Saturday, Feb 17, 2007 at 18:40
Saturday, Feb 17, 2007 at 18:40
Gday kiwicol
No join in my top radiator hose....I think GQ's 2.8 was set up a bit different to the GU's......but, I d try anyting...
Cheers andrew
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Reply By: Member - 'Lucy' - Saturday, Feb 17, 2007 at 15:37
Saturday, Feb 17, 2007 at 15:37
Stefan.
(1) To fix the head or the head gasket the head has to come off for both, so the idea is to try and determine the actual cause rather than a hit & miss approach. (Yeah! Iknow - preaching to the converted but people tend to loose sight of this)
(2) If engine gases or air (from water pump) are causing it, you should see bubbles in the overflow tank
(3) There is a simple
test that can also be done to determine whether or not thereare engine gases in the coolant.
If the above are excluded (Head, Head Gasket & water pump)
(4) Possible O-heating causing expanding fluid to push past radiator cap. However it should return to Radiator on cool down.
(5) Compromised cooling sytem (leak) allowing pressure to release and coolant to boil off into overflow tank.
If these are excluded also (O-heating, leaking) then you have a 'situation' which I have no idea about.
So firstly try and pinpoint from 1-5 above where the problem is eminating from, then you can tackle what the exact cause is.
AnswerID:
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Reply By: Smileyone60 - Monday, Feb 19, 2007 at 11:52
Monday, Feb 19, 2007 at 11:52
G'day.....
I have one sitting in the
shop here at the moment...which had the same symptoms.
He left it alone till it blew !!! Now he can't afford to repair it.
Wether its the head or the gasket...your going to have to find out by pulling the head off. This guy delayed & now its costing him a head & some !!!
THis one was severely cracked in sveral
places.
Good luck.....
AnswerID:
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Follow Up By: GQ_TUFF - Monday, Feb 19, 2007 at 19:18
Monday, Feb 19, 2007 at 19:18
Gday mate, The problem is air in the radiator, it has had different people (mechanics) say it could be different things. Now I have no problem repairing it, I just want to make sure its the gasket or head before I pull it and not another cause.....which brings me to the Co2
test, some say it cant be done on a diesel some say it can, if somebody can tell me for sure that it is combustion gas in the radiator then I will book it in yesterday.....I just want to be as sure as I can that its the head before I start the job cause I would be bleep if I did that and it still did it.
Andrew replied above he had the
test done with great results and fixed his head, he has same symptoms again 2 years later and this time the Co2
test is negative so what
test can I have done to prove its the head before I do the repair??? Help please!!! I know it is pointing towards the head
Cheers Stefan
FollowupID:
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Reply By: messinaboy - Tuesday, Feb 20, 2007 at 10:17
Tuesday, Feb 20, 2007 at 10:17
Hi, one thing you can
check is the bottom radiator hose,if the hose is soft, as the motor reves go higher it tends to suck the hose togeather and block the water flow,over heat and throw the water out.Thats why some bottom hoses have a wire spring in them.If you drive around slow (at low reves) no problem,higher reves the water pump pumps harder,with the restriction of the radiator the hose startes to
cave in. Something to
check,hope it helps.
AnswerID:
222867