To try and cure the problem of the coolant boiling over As some of you know I bought an alloy rad and a new thermostat and changed the hoses.

 

 

While all the hoses were off I managed to flush the system through each one of the holes with the front pipes off to check the flow, and it all seemed good. managed to get rid of all the minging brown water too. Got the new rad fitted and bled up ok, but something still didn't seem right.

 

After every test drive with my ear close to the rad cap I could here the coolant bubbling, It was no where near as violent as it was from the old rad, it was shaking the overflow bottle or leaking out onto the road. (the old rad cap was rated at 1.2 bar, and the new one is at 1.3 bar) and the temp gauge wasn't shifting at all, just showing a nice running temp.

So I haven't really been driving it, just little runs after trying to bleed it a little before each one, (because the level had dropped so needed topping up)

 

I took it to work with me the other night and it's only a short drive and I don't even think I put it in positive boost, but the sound was still there when I stopped, I could also here a bubbling sound towards the back of the engine but everything was still dry. After a few hours I opened the cap to see what the level was like and it hadn't really changed but there was some pressure built up.

 

 

Anyway something finally gave yesterday and it pissed all the water out, I wasn't far from home though so managed to get it back ok without the temp even moving. I took a video when I pulled over, lots of steam but hard to see where it's coming from, I thought it was from the turbo pipe which was weird but I think it's just dripping there from somewhere above.

 

 

So I was mentally preparing myself for a head gasket change. Even when I thought It could just be a hose somewhere or a blockage, I figured If I'm going to go to the effort of taking the plenum off I may aswell go the hole hog and get the head off too.

 

Me and a few friends are going to attempt it on my drive while the weather's still nice.

 

So where's the best place to get the kit from? is there a write up any of you have used and would recommend? and what other jobs should I do whilst the head is off?

 

My thought's were valve stem oil seals, full egr delete, water bypass, replace any and all hoses (where best to buy them from?) and not sure if it's possible, but can I change the piston rings with the block still in?

 

Also it did cross my mind that with the manifolds' off, it would probably be wise to do something with the turbo's too. is there a recon service or is it just better to buy new, or is it just as cost effective to upgrade them and get bigger one's?

 

I'm aware this is going to be a costly exercise, but does anybody have a ball park figure how much I'd save between doing it myself or paying somebody else to do it?

 

Luckily I think I should be able to get the head skimmed at work so that could save a few bob.

 

As always advice comments and support welcome.

Just try...change the rad cap to an OEM one, the one that cane with my japspeed rad started pissing out coolant.

P.S pulling the head in situee is a bell! The turbo makes taking the manifold off seriously messy, might be a lot easier to pull the block and have at it.

check the water pump chinisese crap are a problem use oem only you can tell with the number of blades

Just try...change the rad cap to an OEM one, the one that cane with my japspeed rad started pissing out coolant.

P.S pulling the head in situee is a bell! The turbo makes taking the manifold off seriously messy, might be a lot easier to pull the block and have at it.

 

Got two rad caps with the rad, tried it with both of them (it appears it's not actually a japspeed rad, just a generic alloy one with no markings on it, and they've thrown in an extra japspeed rad cap)

 

Any idea where it could be leaking from?

 

As for pulling the block although I could probably get access to a crane it's then having somewhere to put it once it's out. my garage is not available at all. and the dinning room table may not be appropriate.

 

If the turbo's are coming off anyway I figure they could be removed with the manifold so would make things a little easier. plus I don't fancy uncoupling the box on my drive either, that's a **** on a lift nevermind been on your back.

 

check the water pump chinisese crap are a problem use oem only you can tell with the number of blades

 

I think although I may need to check, but Jeff may of changed the water pump when he did my timing belt in December. If not I may aswell add it to the list of jobs to be dune.

Anyone else with any insight? can the piston rings be changed with the block in?

 

Any other jobs I could do while the heads off?

Hi Steve, just having a five minute break from a cambelt and rocker cover job, will pm you later with some best options for you.

 

Jeff

Before you rip it apart I'd make double, double certain it is the head gasket. Check for oil in the water (sounds like you don't have), exhaust gases in the water (you may have) and water in the oil. Then do a compression test, if all of those are good then the head gasket is probably ok. There are quite a few places for water to leak, and water bubbling back into the overflow tank is quite normal - it's what it's there for!

yeah there doesn't seem to be oil in the water, and looking down the oil filler cap there doesn't seem to be water in there either, although there is the odd bit of white smoke out of the exhaust.

 

I did a compression test and one of the readings was suspect, however it was a stone cold engine and my battery was on it's way out. when tried again warm it did seem ok.

 

There was however (before changing the rad and flushing the system) some white foam stuff would appear in the rad while bleeding. but not straight away, only when up to temp so was assuming that was coming from behind the thermostat. put it down to the k seal it's had over the years.

 

Here's the other thread with the compression test results etc

 

http://www.300zx.co.uk/forums/showthread.php?177037-Big-F*cking-Problems

Sounds like Stevie is getting the big spanners out !

haha, big spanners aren't the half of it bud....

I thought it passed a sniffer test?

yeah it did, that's the annoying thing.

tried it a few times, from cold and when warm...

 

I figured it could be on it's way out, hence when it was warm the compression test was fine too, but as I've been taking it for little drives it's been getting progressively worse..

 

A touch odd...

Wheres the rest of the leak tester,should have 2 chambers with fluid not one ? comp tests are pointless with headgaskets fails unless its blown so bad its gone between two cylinders.If you dont bring it on boost does it behave longer Steve ?

Well when it's running it behaves sound, since changing the rad I could give it a good boost and all would be fine, it was only after knocking it off and listening at the rad that you'd know anything was up. Until of course it pissed out all the water.

 

The block tester was what my mate brought home from work, that's all that was in the box with a bottle of the fluid. Said it would turn one colour for petrol and another for diesel. I thought it looked the same as the one vodkashots posted a link to.

 

I could give a cylinder leak test another go, but we couldn't get the piston in the right position.

 

Anything else I could try?

Ok so been in the Dominican for a couple of weeks so haven't had chance to do anything with the zed, but one thing I have noticed is when it's first started up it sound like it's misfiring now, but only for a couple of seconds then it settles out, I'm guessing water in the cylinder... haven't had chance to whip the plug out yet but i'll get round to it. Guessing that would be the nail in the coffin though for the head gasket????

If you had enough fluid in there to make it miss it would steam like a powerstation, also much more and you would likely hydrolock the motor and bend the rods. Also you would probably have contaminated oil, as it seeps through and gets in the oil.

not sure how much you have to spend on fixing this... but if you're going to be looking for another motor keep my car in mind... we could come to some agreement.

If you had enough fluid in there to make it miss it would steam like a powerstation, also much more and you would likely hydrolock the motor and bend the rods. Also you would probably have contaminated oil, as it seeps through and gets in the oil.

 

Well I'm taking that as reassurance, but I am only talking a couple of seconds and then it sound's sweet again. when I get some normality back in my working pattern i'll get my teeth back into it and get some definite diagnostics done. although I'm struggling to think what else other than trying for the cylinder leak test again.

 

not sure how much you have to spend on fixing this... but if you're going to be looking for another motor keep my car in mind... we could come to some agreement.

 

I don't like to say never, but I'm pretty confident in a rebuild instead of replacement, the millage if genuine is to low for me to swap it out, and if I'm prepared to just rebuilding it, atleast if things go wrong thereafter I know it'll be something I've (or my team) done and not inheriting other problems.

 

My mate is rebuilding a ca18det from an S13 at the minute, it's in bits on his drive, so I'm letting them get practice on that before ripping mine apart. To keep costs down through friends of friends we've managed to find somebody to rebuild turbo's, I can get the heads skimmed at work for nothing, so it's just the gasket kit, hoses, and whatever else is going to be a good investment.

 

I also figure if I do it myself I can make it look pretty, maybe relocate some things, remove others, and clean, polish. powder coat and paint so that the engine bay looks as clean as the bonnet.

 

However anything could happen between here and there, so as I said, never say never.

 

And still this is all a worse case scenario, it may not need something as extreme as that....

any further on buddy ?

Unfortunately not bud. been busy working. may get some time to have a look over the weekend.