Boiling Turbo

[rob323]

I had exactly the same problem on an old familia (B6 short nose crank), but the cause was the end of the short nose crank slowly twisting off and retarding the static timing by huge amounts. The other symptom was a huge loss of power, so much so that it would struggle to get up to 80 kph.

[bjones]

Mate

Ive had my turbo LAVA RED after blowing an under bonnet supercharged V8 XB Falcon into the weeds multiple times in the early days of my car biuld and never had bubbling water in it.... ( I have a really bad phone pic of it too somewhere) I did allow it to run down cool though.

If it was running lean did you here a sound like a tin getting shaken with ball bearings in it, thats the sound of pinging!! (WHILE ITS RUNNING)

what Air fuel ratio are you aiming at???

BJ

[ampz]

You can idle lean and retarded (check your setup with a timing light olboy, i'm assuming you have here) without glowing manifolds easily.

I side with the others here in saying you most likely had air in the cooling system.
Be careful to check that your radiator cap is the highest point in the cooling system otherwise as air rises to the top, it will get trapped there and once the coolant is allowed to expand it will boil.

The FM manifold places the turbo just below the level of the radiator but if you run flexible hose above the turbo, it will trap air in there.

Also, make sure you check your throttle body coolant hoses if fitted.
I had one of those hoses work loose (or i forgot to tighten it) and would get occasional air into the system that would sound the same. Coincidentally it would also sound like water sloshing around in a bucket straight after starting the car which was quite peculiar.

[Lokiel]

sorry the water is boiling in the turbo, I can here it boiling after the engine is off
I only need to warm the engine up and the turbo gets realy hot so that the water boils when it's not circulating
I don't even have to drive the car
I don't think it does it when the engine is running only after shutting down
It's a new second hand conversion

I had this same issue about a month ago and it turned out to be that my radiator thermofans weren't activating (I was using an Adaptronic e420c ECT graph with my e440 which turned out to read 25-30C too low for te e440). I knew that something was up with my water temperature because I've made the linear water temperature gauge mod (see http://www.mazda-speed.com/forum2/index.php/topic,21534.0.html) and could see that the gauge was reading much higher than normal (normal sits at 1/3, was reading 2/3).

Turning on the air-conditioner, which activates the thermofans, dropped the water temperature back to normal. Check if your thermofans are working by allowing the car to idle for a while, or go for a short drive and pop the bonnet with the car idling; the fans should come on temporarily as the water temperature climbs to their activation range. Another thing to try is drive around with the air conditioner on, then turn the car off and pop the hood to listen for it boiling.

Another common possibility is that you thermostat is seized and needs to be replaced.