coolant expansion tank overflowing got me stumped

[toddross]

Hi all. I got a question. My 2002 navara 4wd with a zd30ddt has been over flowing from the coolant expansion tank when I do long trips on the open road. I can go 4wding or do short trips and wont have a problem. Done a preasure test today and wound over the engine without glow plugs in and 15 psi on the radiator. No sign of coolant coming out. Recently i Put in new thermo stat. Didnt fix the problem. Iv had the problem since I pulled the radiator out then took it in to a radiator guy to get a new seal put in. He also flushed out the radiator. Im thinking either a very small crack in the head or (im hoping) a blocked water jacket or something

 

[Chris T]

Radiator Cap

Have you replaced the Radiator cap these systems build up pressure thus forcing some coolant out then a correctly operating cap will allow coolant to be returned to the Radiator .if faulty coolant will keep building up in over flow tank
Chris

 

[Old.Tony]

Chris has a good point. The most common cause of these problems is a weakened spring in the radiator cap (heat does that after a while).

 

[toddross]

It had cap (0.9) from a big bin that the radiator guy gave me when the radiator was flushed. It looks brand new but wasnt out of a packet. The radiator guy said the one that was previously on it was the wrong one an was stuffed anyway. Repco and everyone ive talked to said its the right cap. Would it be worth getting a higher preasure cap?

 

[4 naving]

no don't put a higher pressure cap on it will cause other dramas and possibly blow the radiator. Is there any air in the system? this could force the water out when hot.. also did you put the fan shroud back on properly as this is an important part in controlling air flow.

 

[unkn0wn]

as i don't trust the standard guadge, would you happen to have an aftermarket Temp guadge installed to check water temp?

If temps staying consistent when its blowing out, you have a pressure problem. something blocked etc. also pretty sure rad places can pressure check you system cheap enough?

if its rising then you have a cooling problem...possibly anywhere.

 

[Insanenavara]

Had similar issue when my 06zd30 blew the head

 

[toddross]

I just have a standard gauge. But it stays just below half until I loose about 2 litres out of the top of the expansion tank plus watever the expansion holds. With a preasure problem what are all the causes. Is there plugs on the engine block that I can open up to run water through to clean out?

 

[toddross]

Yup fan shrouds on properly.

 

[ben85]

my bet is cracked head/head gasket.

try a new genuine radiator cap 1st.

can u smell coolant in the exhaust fumes?

get your coolant tested for combustion gas. in fact, go out in the morning when the engines cold, top up the radiator - leave the cap off, start the engine. if you have bubbles coming out of the coolant you have combustion gas entering the cooling system, which will be from the head/head gasket. if not you may still be ok.

is there's no sign of where the coolant is going i'd say its probably going into the engine.

 

[toddross]

Ok I think il get the coolant system tested for combustion gasses

 

[Black Beautie]

Crack head

 

[ben85]

Crack head

is that crack head or cracked head???

 

[d22-s2]

This happened to me 2 weeks ago, was driving from Brisbane to Dubbo, stopped in Goondiwindi and i noticed green liquid round the drivers wheel arch and side steps.. thought nothing of it, went n got something to eat.
when i came back it dawned on me what it was. I was shitting bricks because i was driving back to Melbourne and it was friday arvo, so if something was gone i would of been stranded.

went to a Repco service center, the guy there pressure tested my radiator and did something with the head. Couldn't fault it at all n sent me on my way (didnt charge for anything the champ)

Got to dubbo and it had happened again!

did it a bit coming back from Dubbo to Melb but not as much.

I did top up the coolant as I went along, but the strange thing is it hasn't happened since.

Goes in for a service soon, hopefully they can tell me something.

 

[ben85]

This happened to me 2 weeks ago, was driving from Brisbane to Dubbo, stopped in Goondiwindi and i noticed green liquid round the drivers wheel arch and side steps.. thought nothing of it, went n got something to eat.
when i came back it dawned on me what it was. I was shitting bricks because i was driving back to Melbourne and it was friday arvo, so if something was gone i would of been stranded.

went to a Repco service center, the guy there pressure tested my radiator and did something with the head. Couldn't fault it at all n sent me on my way (didnt charge for anything the champ)

Got to dubbo and it had happened again!

did it a bit coming back from Dubbo to Melb but not as much.

I did top up the coolant as I went along, but the strange thing is it hasn't happened since.

Goes in for a service soon, hopefully they can tell me something.

keep checking that coolant each time you drive it!

if you notice it losing coolant top it up and check for bubbles in the radiator.

 

[d22-s2]

keep checking that coolant each time you drive it!

if you notice it losing coolant top it up and check for bubbles in the radiator.

thanks for the advice. will deff be keeping an eye on it

 

[d22-s2]

Just an update.

Turns out it's either the head gasket or the head.

I'm currently on holiday so when I get back I reckon I'll pull her apart n see what's going on.

 

[ben85]

from everything i've heard its most likely to be the head.
whatever you do make sure u get it xrayed and pressure tested before you put it back together.

 

[Mister2]

Yup, similar issues and it turned out to be a crack in the head.

 

[d22-s2]

Yeh I've pretty much convinced myself that it's the head, seems to be so common with these engines