Another DA9 Turbo

**mooshie** · 19-10-2008 11:34 AM

I have just boosted my JDM B18C to 8PSI and most things seem to be good but i have a couple of questions and possibly issues.
I started out with only 1 12" slim fan on the standard radiator and when I stopped the water temp would go up to just over halfway and come back down when i started off again. Put another 10" in there and solved that problem.
Now when I stop and turn off the car, if I leave the ignition on the fans run for about a minute and then switch off, water temp seems to be fine. However, there is a noise like bubbles flowing through the top radiator hose. Not a constant bubbling like it is boiling but a small squelching noise every approx 10 seconds. I let the car cool and then open the radiator cap and I am missing about 100ml of coolant which seems to be in the overflow bottle. this has happened 4 times and has got me worrired!
Oil temps seem to be a little high too, after about 10 mins of driving it sits on about 240F and under heavy boosting it might go up to about 255F and then come back down. My Autronic computer cut the power at 6000rpm once at this temperature. Obviously an oil cooler is the way to go, but will this help with the coolant too?

Other than that, gee it is a bit of fun.. I have a GT2860RS on there and it was chosen because I wanted something very responsive and driveable, not all that interested in extreme top end power.
Dump is split from the wastegate and is 2.25 inch out to 2.5" after the intitial tight bend wastegate dump joins up about 20cm later, then goes 2.5" till just after the high flow cat. rest of the exhaust at the moment is still a 2.25" old NA crush bent system which will be upgraded at a later date.
Management is Autronic SM4 with electronic boost control, high/low switch, launch control and all the other goodies that are not active yet. Made 157KW at the wheels, think it will probably do about 165-170 when the exhaust is upgraded.

**EKVTIR-T** · 19-10-2008 11:36 AM

Congrats mate.Get that exhaust sorted asap

Must be a blast to drive now

**Lukezen27** · 19-10-2008 11:52 AM

Sounds like a blown head gasket bro

I had the same problem with bubbles flowing through the top radiator.. and the coolant would not suck back into the radiator.

Got wost and wost so I got a comp test and cylinder 4 was way down...

= small hole in the gasket

Replaced the HG and added ARP head studs at 70+

Not one problem since

I'd upgrade to 3" exhaust, I've upgraded to 2.5" with a 10kw gain but my motors a lot smaller than yours..

And upgrade the radiator if I was you.. and that will in turn help your hot oil

**mooshie** · 19-10-2008 12:08 PM

not sure if it is the headgasket, no water spitting out the exhaust and I have been refilling the radiator from the coolant overflow, which seems to fill up each time, ie. not losing any coolant

anyway here are some pics:

**Lukezen27** · 19-10-2008 12:13 PM

Originally Posted by mooshie

not sure if it is the headgasket, no water spitting out the exhaust and I have been refilling the radiator from the coolant overflow, which seems to fill up each time, ie. not losing any coolant

anyway here are some pics:

Mine never spitting water out the exhaust, the hole was in the cooling jacket only and very small..

water jacket = filling up the overflow bottle

I got just small bubbles for about 6 months without any other problems...

Looks nice bro

**mooshie** · 19-10-2008 12:22 PM

mmm.. bugger. could you hear the bubbles all the time when the engine was running or only when you stopped? might have to get a comp test done and see what it turns up.

Thanks.

**Lukezen27** · 19-10-2008 12:25 PM

Originally Posted by mooshie

mmm.. bugger. could you hear the bubbles all the time when the engine was running or only when you stopped? might have to get a comp test done and see what it turns up.

Thanks.

my exhausts is to loud to hear anything.. so no I didn't hears anything

But yours dose sound the exact some as mine at the very start..

Get a comp test its the only way to really tell

**stocky** · 19-10-2008 01:53 PM

I hate to say it too but it sounds like a HG. In my DA, it would pressurise the coolant system and the overflow would slowly fill after a period of driving. It got worse when I kept blowing coolant hoses and overheat. Culprit was a small leakage from the combustion chamber to the coolant jacket in the HG.

I do hope yours is something else though, fingers crossed.

**mooshie** · 19-10-2008 04:06 PM

so would I be right in saying that the gasket has probably had a small hole for a while, and it is only now that it is seeing positive pressure that is forcing the coolant out?

Luke, you said you drove for 6 months like this? Did you just keep refilling the radiator? not that I am going to risk that.

**Lukezen27** · 19-10-2008 04:14 PM

Originally Posted by mooshie

so would I be right in saying that the gasket has probably had a small hole for a while, and it is only now that it is seeing positive pressure that is forcing the coolant out?

Luke, you said you drove for 6 months like this? Did you just keep refilling the radiator? not that I am going to risk that.

That's correct!

Its more than likely I had this problem before boost but didn't show up very often but once boosted it started getting wost and overheated once..

But yeah for 6 months I just filled the radiator up by using the overflow bottle..

Don't risk it, one overheat can kill your ringing

**stocky** · 19-10-2008 05:29 PM

Originally Posted by mooshie

so would I be right in saying that the gasket has probably had a small hole for a while, and it is only now that it is seeing positive pressure that is forcing the coolant out?

Yep, that's what I thought too. When I changed my HG, it was evident where the coolant was seeping. It's prob a weakness that posed no problems n/a, only manifesting once it was pressurised.

I personally thought that it was because of the 0.64a/r rear housing on my turbo being too small, but I dont know, this is all speculation on my part.