Turbo center housing leaking coolent?
 

Anybody ever have a center housing crack or something where it leaks coolant out of somewhere besides the fittings? It’s a GT3071R WG

I’ve been searching for a coolant leak for like a year now. Small whiffs of it on shut down but could never find it with pressure tests. I kept on thinking it had to be the fittings on the turbo I changed them several times and it changed nothing. Pretty much the whole center section shows evidence of coolant. It finally got a lot worse this weekend. After first run at autocross the top of the center was wet with coolant and because it was hot it dry’s fast. A little splattered on the under tray probably a dixy cup full. Once fully warm it seemed to stop and the system maintained normal pressure and no more coolant showed up on the under tray. . After the first day of this I pressurized it to 20 psi after it cooled down and could not find any leaks it held pressure over night. First run day 2 same thing again. But now after the event it finally is dripping out with no pressure and the car cold. The top of the center section is wet above where the water fittings are its like coming out of the flange area where it bolts to the turbine housing I think.

I did not think this was very likely but maybe it is?

Any pictures? What fittings do you use? Can you pressurize the turbo separately?

Yep pressurized it now and can clearly see it with no doubt squirting coolant out of the casting at the corner of the spotface in the top around the oil feed up next to the turbine flange.

https://www.miataturbo.net/attachmen...ine=1436767935

Cracked chra? Wow that's a first for me.

Only bob could crack a chra. I would award props, but, you know....

Im wondering if this has something to do with years of extreme heat cycling, but then I think about diesel semi tractors or the like that probably cycle more without this issue. Interesting.

Not many semis run gt30s lol. Their turbos are like 5 times the size.
<br />Maybe you just got a dud?

Never said they did, and I don't get you point. How does the model of turbo have anything to do with idea of cyclical thermal fatigue? Assuming they are both oil/water cooled of course.

From what I've seen big diesel stuff, like turbos, are overbuilt.
<br />
<br />Also diesels see much lower EGTs.

True, maybe it was a bad example.

How about:

Im wondering if this has something to do with years of extreme heat cycling, but then I think about "insert high cycle, extreme duty corollary here" or the like that probably cycle more without this issue. Interesting.

Bob is that the same turbo you installed in like 07?

I replaced it once prior to 08 I think. A broken intake valve on a stock internal backup motor resulting in chunks of piston going through the turbo took out my first one. I think it was 07.

remove water lines, problem solved.

till the oil cooks.

that doesnt happen.

why is it cooled then? The turbine housing it is in intamate contact with gets red hot.

<p></p><p>&nbsp;</p><p>My understanding is that the main benefits of watercooling the turbo are that it acts as a heatsink after you turn off the car. Aside from the obvious XX Degrees cooler it would be whilst the car is running.</p>

While pulling the water lines may jot he the best long term solution you can definitely run it with no water.

https://www.miataturbo.net/attachmen...ine=1436804054




This debate has been going on for years...

aidandj is correct in that the turbo will not self-destruct in a short period of time if run with no water. We have many examples of this, and of course some turbochargers have no provision for a water-jacket in the first place.


Schuyler is also correct in that the presence of the water jacket serves to draw heat away from the bearing section after the engine has shut down. During operation, oil is flowing through the turbo sufficiently quickly that it doesn't have time to absorb enough thermal energy to break down. After engine shut-off, by comparison, a relatively small amount of oil becomes stagnant in an area containing a relatively large amount of heat.

This latter argument is supported by the recommendations of turbo manufacturers, including a description of the ideal routing of water lines to promote thermal siphoning of water after shutdown. Turbo manufacturers, of course, have a vested interest in ensuring that their products function reliably, and so I tend to trust them in such matters.

Here is a white paper from Garrett which describes, in their opinion, the benefits of water-cooling and the optimum arrangement of water lines: http://turbobygarrett.com/turbobygar...er_Cooling.pdf

I would have accepted:

https://www.miataturbo.net/attachmen...ine=1436805119


but I will counter with:

https://scontent-lhr3-1.xx.fbcdn.net...18&oe=561B5479

Autocross = crap load of short duration High loads and turning the car on and off.

probably what accelerated the cracking of the center section. initial leaks were only whitnessed during warm up and cool down. Took a year of use before it grew to where I could actually whitness where it was comming from for sure and it would leak when cold.