GQ using water.

Submitted: Wednesday, Aug 11, 2004 at 18:29
ThreadID: 15478 Views:3253 Replies:6 FollowUps:3
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G'day fellas I have a customers Nissan Patrol in my workshop at present which is using water.

I replaced the leaky water pump last week assuming that was the cause,as this truck runs very well.

There is no sign of a blown head gasket or cracked head,it does not hydrolic when you start it (hot ot cold) all the plugs were rusty when I removed them last week,I am wondering do these rigs have a problem with the inlet manifold?.

Compression is spot on,and like I stated this rig runs like new,it just uses water,like two liters every five days or so.

I have not pulled the head as yet as I do not want to charge my customer for work that was not required.

This is quite odd that I cannot find the fault,so I look to you fellas for an answer.

Thank you in advance.kik
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Reply By: mr diamond - Wednesday, Aug 11, 2004 at 20:11

Wednesday, Aug 11, 2004 at 20:11
did any thing show up when you presure tested the cooling system.
just finished a head job on a v6 pajero slight crack around one of the inlet valves welded up good as gold now.
AnswerID: 72183

Follow Up By: Member - Tim D (VIC) - Wednesday, Aug 11, 2004 at 22:43

Wednesday, Aug 11, 2004 at 22:43
my GQ had the same problem replaced the water pump had the welsh pugs replaced cost me a fortune and still after this it was using water. Later found out that it was a cracked head
FollowupID: 332422

Reply By: kik - Wednesday, Aug 11, 2004 at 21:34

Wednesday, Aug 11, 2004 at 21:34
There was some slow pressure loss,but nothing I could really put my finger on.
My main concern is that all the plugs were rusty which is why I have asked about a possible inlet problem.

The car runs perfect no comp loss no misfiring no contaminated oil/water,not even over pressurising.

If need be I will strip the lot down but I would prefer not to waste my hrs,or my customers money.

This is odd to say the least. I am not at the stage where I am scratching my head I would just like to save myself and my customer some time.
AnswerID: 72202

Follow Up By: mr diamond - Wednesday, Aug 11, 2004 at 21:55

Wednesday, Aug 11, 2004 at 21:55
that is an odd one.
i have a gq that lost water some times not always and i couldnt find it.
i have a rb30 so not sure if this will help but the water pipe to the inlet manifold hose has a sleeve over it and it had a small hole in it but it wouldnt always leak i looked and looked till one day at the shopping centre i noticed a puddle under neath so i was playing around with the hoses and there it was i just happened to move it the right way and out she come.being a mechanic my self i still havnt fixed it yet but i did pull the sleeve up over the hole and hasnt leaked since lol.
good luck we all love head ache jobs dont we
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Follow Up By: Member - Ed. C.- Wednesday, Aug 11, 2004 at 22:09

Wednesday, Aug 11, 2004 at 22:09
Not familiar with Nissan petrol engines, but if it's an alloy manifold which has coolant circulating through it, I'd be willing to place a small wager that you are looking at internal corrosion in the coolant gallery, most probably caused by insufficient/incorrect coolant mix over a period of time...
The point you make about the rusty spk plugs definitely suggests that the leak is in the manifold...
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FollowupID: 332410

Reply By: Bilbo - Wednesday, Aug 11, 2004 at 21:57

Wednesday, Aug 11, 2004 at 21:57
You could be on the right track with a possible crack in the inlet manifold - if it has a water jacketed manifold. I don't know my way around these vehicles these day. 20 years since I was mechanic.

Try plugging the inlet and outlet hoses on the manifold and pressure test the cooling system again. If the "slight drop" in pressure doesn't happen, then the manifold is cracked inside.

AnswerID: 72206

Reply By: Martyn (WA) - Wednesday, Aug 11, 2004 at 22:34

Wednesday, Aug 11, 2004 at 22:34
If you are sure that the head is ok, which on these is suspect, they do crack, the amount of water you're using suggests something more adoo here, the side plates on the engine corrode they are ally, I'm more or less certain there isn't any water connections in the inlet manifold, if the water was getting into the cylinder at this rate I'm sure there would be evidence of a missfire, I'm assuming this is petrol not diesel and the plugs you talk about are spark rather than glow plugs. The other common failing point is the core plugs on the back of the engine, there is one on the head which can be done by taking the head off unfortunately, or there is the other two one which is inside the bellhousing, this one is evident by coolant dripping out of the gearbox bell housing drain hole, which can get blocked with friction dust.
If you still can't find the leak put a pressure test on the system up to about 9 to 13 psi and look for leaks. The ally fron engine plate can leak between the head and the block again a quick look will tell you the answer. If this is leaking you may have to take the engine out, the seal is a rubber o-ring, the o-ring goes hard and cracks over time. Any emulsified oil, water in the rocker cover? Head gasket or oil cooler rooted.
Well that lot should start you off, hope something helps.
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AnswerID: 72216

Reply By: kik - Thursday, Aug 12, 2004 at 00:05

Thursday, Aug 12, 2004 at 00:05
Wow great responces from obviously well educated people thank you so much for your prompt and genuine replys.

Ok let me go through what I have done so far just so you all know what has and has not been done.

Car came to me with water using problem last week.
I diagnosed a leaky water pump bearing seal was gone (this was a non gen pump) I replaced with genuine from Nissan down in Geelong.

I also done a full tune including dizzy cap plugs leads ect ect all genuine (I hate come backs).
I also fixed some oil leaks greased the front end ect.

While I had the leads off and the dizzy cap off I removed the rocker cover and gear and re-torqued the head,head studs were at 40lb I assume from detonation as the car was way advanced when it came here.

This I also thought may have contributed to the water usage.

I did a pressure test at 15 psi and over the period of 30 mins it only lost 4lbs pressure.

So I assumed all was well,I had the truck on the hoist and went right over it and found no water leaks what so ever.

There was slight condensation in the rocker cover,but as this truck is used mostly for short trips this is quite normal.

If there is infact no water connections to the inlet (I haven't looked yet) I will have to pull the head no question.

I am hoping there are as I will disconnect the hoses and give the truck back,and wait and see what happens from there.

Once again guys thanks heaps for the replys.kik
AnswerID: 72229

Reply By: Member Eric - Thursday, Aug 12, 2004 at 07:47

Thursday, Aug 12, 2004 at 07:47
remove the manifold and leave water hoses connected (if there are any ) . If no water comes out under pressure test . Bet on Head
AnswerID: 72239

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