Hi all, so short story, been a fan of a Z for a while picked one up a 1993 NA August, got some work done, all belts changed, water pump changed, rocker cover gaskets, and some wiring done only to realise afterwards that i got a head gasket issue, leaking exaust fumes into coolant :( not happy had i k own before i would have fixed that first, my mechanic is estimating around min 1k to fix not sure what to do now, its an NA so its not the most sought after model

Has anyone wver done a head gasket on 300zx, does the engine need to come out?

I've never used the stuff but some people swear it works. Do your own research on K seal.

Just pull the engine. I believe an NA can be done in the bay but by the time you’ve got down to that point you may as well of pulled the engine and done a proper job.

Hi all, so short story, been a fan of a Z for a while picked one up a 1993 NA August, got some work done, all belts changed, water pump changed, rocker cover gaskets, and some wiring done only to realise afterwards that i got a head gasket issue, leaking exaust fumes into coolant :( not happy had i k own before i would have fixed that first, my mechanic is estimating around min 1k to fix not sure what to do now, its an NA so its not the most sought after model

 

 

How have you determined the problem, what method?

 

Has anyone wver done a head gasket on 300zx, does the engine need to come out?

 

Can be done in the car, not too bad on a non turbo

 

I've never used the stuff but some people swear it works. Do your own research on K seal.

 

Mmm, tried this stuff twice and did not work either time.

Here is a non turbo I did around four years ago, in this instance the cam had seized ripping the belt teeth off and crashing the valves and pistons.

 

I did have a couple of heads ready to fit so not too bad, a good days work for sure.

 

Jeff

 

 

 

 

 

- - - Updated - - -

 

 

 

 

I did a block test, it turned yellow, coolant system under pressure is taking coolant out the overflow pipes

How have you determined the problem, what method?

 

 

 

Can be done in the car, not too bad on a non turbo

 

 

 

Mmm, tried this stuff twice and did not work either time.

 

Sent from my Pixel 2 using Tapatalk

All finished and topping up >>>

 

 

 

 

I did a block test, it turned yellow, coolant system under pressure is taking coolant out the overflow pipes

 

Well the block test method is the least accurate method, and some doggy parts of the motor trade its well know as a money maker as it is can be so convincing to see it change colour, doggy mechanics just breathe into it when the customer is not looking, and they are very sensitive.

 

But if your getting over pressure etc. then it likely you will need the heads crack tested and skimmed to get the best results.

 

Jeff

I did the block test myself also, here is a video of my radiator under pressure at first i thought it was air stick

 

 

 

 

Sent from my Pixel 2 using Tapatalk

I did the block test myself also, here is a video of my radiator under pressure at first i thought it was air stick

 

 

 

 

Sent from my Pixel 2 using Tapatalk

Here are test results

 

Sent from my Pixel 2 using Tapatalk

I did the block test myself also, here is a video of my radiator under pressure at first i thought it was air stick

 

 

 

Sent from my Pixel 2 using Tapatalk

 

 

Ok that video is not convincing me at all, usually over pressure will shoot the water out like a geezer !! not saying your wrong and it maybe just a small issue that you have caught early. I assume your loosing water out of the expansion vessel ? that could be a bad radiator cap, I would be looking at a few more tests yet to be honest.

 

 

 

Jeff

Nice work, i have alot to learn about Automotive :) growing up loved cars had a 200sx in my youth, but then life got in the way :) now alot more relaxed moved out of London get to do more, sure is better then sitting at a desk writing code, although wife is not so fond of my hobbies :)

 

Sent from my Pixel 2 using Tapatalk

I bought a new caps also, with the cap on it leaks where the overflow pipes are, had these changed also

Ok that video is not convincing me at all, usually over pressure will shoot the water out like a geezer !! not saying your wrong and it maybe just a small issue that you have caught early. I assume your loosing water out of the expansion vessel ? that could be a bad radiator cap, I would be looking at a few more tests yet to be honest.

 

 

 

Jeff

 

Sent from my Pixel 2 using Tapatalk

Hi Jeff, what are tests could i do?

 

Sent from my Pixel 2 using Tapatalk

Sorry correction its coming out of the coolant bypass hose when system is under pressure (with rad cap on), when I take cap off there are no leaks

Sorry correction its coming out of the coolant bypass hose when system is under pressure (with rad cap on), when I take cap off there are no leaks

 

You sound surprised by that.....when you take the cap off, it depressurises the system.....

No no not suprised just trying to understand how this cooling system works, by no means im mechanic, but i have bought a book!! ;)

You sound surprised by that.....when you take the cap off, it depressurises the system.....

 

Sent from my Pixel 2 using Tapatalk

Hi and welcome mate!

 

Whilst my initial thought was to concur with your own diagnosis; Jeff has many, MANY, years experience working on these cars - so his advice is second to none. Don't immediately condemn the head gasket because a mechanic inexperienced in the 300zx says so - or even if your own testing might indicate it.

 

I'd suggest getting your car to a specialist. Rochdale is a long way from Bristol, but you cannot go wrong with taking your ZX to Jimmer.

Hi Richard

 

Thank you, much appreciated, i was actually in conversation with Jeff earlier today and he mentioned Jimmer from Powerzed who i have messaged but i assume he is a busy guy so will wait for him to get back to me, in the meantime i will just stare at the Z from my window :)

Hi and welcome mate!

 

Whilst my initial thought was to concur with your own diagnosis; Jeff has many, MANY, years experience working on these cars - so his advice is second to none. Don't immediately condemn the head gasket because a mechanic inexperienced in the 300zx says so - or even if your own testing might indicate it.

 

I'd suggest getting your car to a specialist. Rochdale is a long way from Bristol, but you cannot go wrong with taking your ZX to Jimmer.

 

Sent from my Pixel 2 using Tapatalk