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Hi Guys,

As thread title suggests I've got oil in my radiator.... Car is a '97 Stagea (RB25DET) converted to manual last year. Car doesn't miss a beat or run hot. Can take the radiator cap of and when it is running it doesn't blow bubbles or anything but their is defiantly oil from somewhere inside the radiator. Engine has done 155,000. Its not got heaps or anything.

Where do I start and what should i do?

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https://www.sau.com.au/forums/topic/372125-oil-in-my-coolant/
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Might have a cracked head, its definitely a hard one to diagnose..

Theres also a coolant opperated oil coover on some nissans, not sure if your model has got one..

Anything that mixes coolant and oil could be the problem really...

I wouldn't say its a poorly serviced, radiator was flushed and new coolant went in 9,000k's ago so I doubt its that.

Simon how can I check if its the oil cooler assembly?

Its odd in the fact that oil is in the water but no water in the oil if that makes sense? eg. dipstick is just oil and when i did the oil and filter last week no water was in the oil :/

Have a few photos on my phone will upload soon

here are the photos apologies for the quality, iphone @ night isnt really that great....

The pics make it look alot better than it is.....

While I was out their i stuck my finger in the radiator and if u bend it around and feel the top of the tank its got a light layer of the oily gunk on the inside of it.... :-(

254649_2167486061754_1084756809_32540452_8035134_n.jpg

250267_2167486381762_1084756809_32540453_4687164_n.jpg

263231_2167486701770_1084756809_32540454_3606291_n.jpg

Update:

Today I got the car compression tested and TK tested (checksfor combustion gasses in the coolant).

Compression results were as follows: 1. 155 2. 160 3. 135 4. 145. 5. 160 6. 160.

TK test showed NO sign of combustion gasses in the coolant.

When I first dropped the car off and left they called within15 minutes asking for me to come back as they wanted me to show them what I wasworried about because at the time when they first pulled the cap of their wasno oil or anything around but by the time i walked back a little bit hadbubbled up. Mechanic assumes that the headgasket might be on the way out but it’sin its VERY early stages.

He suggested that I lower the boost (currently at 12psi) becausesometimes It hits fuel cut when you boot it (saying that this is very rare as Ibaby it mostly...) and that I just monitor the temperature and oil and coolantlevels.

Just after a couple more opinions on it, perhaps I shouldjust monitor it and keep my eye out for a wrecked stag and buy the donk....

Rough prices was $1500 for head gasket (metal) replacement aslong as my head is fine or worst case scenario $2500.

Thanks once again guys J

a bit strange you have no bubbling in the radiator and the combustion gas test came up negative.

Have you pressure tested the cooling system. i highly recommend this, its a check i do first when any car comes into work with a possible hg issue.

if you have a substantial pressure drop over a short period of time and theres no coolant running out on the ground you have a pretty good idea its going somewhere its not supposed to, like into the oil or into a cylinder!

pricing for headgasket job sounds fair enough, maybe go ahead and do it anyway if you plan on boosting the car more, that way you have a nice strong metal headgasket plus you rule out that being a problem.

Thanks for your input cam,

Yeah it is interesting it came up negative, but he did say that I've caught it VERY early and still suspects HG

I haven't pressure tested the cooling system no, theirs no milkshake in the oil or under the cap... yet

Yeah id do a metal head gasket but in saying that im running a stock turbo and you dont want to put more than 12psi through one of those with a ceramic wheel so is a metal HG really worth it

its worth fitting if you have a blown headgasket anyway, and if you plan on going bigger turbo down the track.

i suggest going back and asking them to pressure test the cooling system and go from there.

you dont have any power steer or transmission fluid cooling through the automatic radiator do you?? just checking as there might be a hole between the oil and coolant tubes and oils getting in the coolant that way.

its it auto?

commodores blow the auto trans warmer into the radiator quite frequently and it looks like you have a blown hg but its actually trans fluid = negative TK test

if you can, run an external cooler for a few days and see what happens

also, get them to drop some oil down the bores and re-do the comp test

and they should do a leakdown test too, that will tell you more info too

Update:

Today I got the car compression tested and TK tested (checksfor combustion gasses in the coolant).

Compression results were as follows: 1. 155 2. 160 3. 135 4. 145. 5. 160 6. 160.

TK test showed NO sign of combustion gasses in the coolant.

When I first dropped the car off and left they called within15 minutes asking for me to come back as they wanted me to show them what I wasworried about because at the time when they first pulled the cap of their wasno oil or anything around but by the time i walked back a little bit hadbubbled up. Mechanic assumes that the headgasket might be on the way out but it'sin its VERY early stages.

He suggested that I lower the boost (currently at 12psi) becausesometimes It hits fuel cut when you boot it (saying that this is very rare as Ibaby it mostly...) and that I just monitor the temperature and oil and coolantlevels.

Just after a couple more opinions on it, perhaps I shouldjust monitor it and keep my eye out for a wrecked stag and buy the donk....

Rough prices was $1500 for head gasket (metal) replacement aslong as my head is fine or worst case scenario $2500.

Thanks once again guys J

seriously could swap in a new stagea neo engine for 2500... including fitment. Simon is on the right trach with the heat exchanger too.

Yeah thats it, could put in another Stagea donk fairly cheap... But how do I know the replacement isn't shagged too?

How hard would it be to put a NEO into it seeing as it's a series one stagea whiche have the pre NEO rb25det

Pretty keen to get it happening as I dont like the idea of not being able to rely on my car...

post a pic as a poorly serviced car will get a rusty looking foam build up in the cap area.... its often mis diagnosed as head gasket.

I still think this is the most likely reason. Give the colling system a good flush and perhaps clean the radiator.

Other than some crap in the radiator, are there any signs of a blown hg?

loosing water?

water in oil?

loss of power /compression?

zorst in the water? (already ruled out).

Even if there is....if it is "midly blown" or "early", I would got straight for the chemiweld. Best case it fixes the problem for $10. Worst caase the motor is a bitch to clean for rebuilding....but as said above you would probably just start with a new one.

Hi Duncan,

Thanks for your wisdom :-)

Ill try and get another photo or 2 today and we'll see the difference from the other night.

In regards to other signs of a blown HG it hasn't shown loss of water or oil yet, but i'm assuming this is because I've caught it so early and the amount of oil is very minimal. But it does feel like it is lacking a bit of power but im not sure how much as I very rarely drive the car hard at all. As you can see it is down on compression between holes 3 and 4 perhaps this is where the leak is.....

I dont really want to put chemiweld or an additive like that into it truth be known.

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