EJ25D head - coolant plug?

[93forestpearl]

I'm thinking this is a plug for coolant, but I'm not 100%. It pretty much mirrors where one would tap the other side for coolant to the turbo.

I'm glad I pulled the motor, because I never would have seen this. Not sure how I missed that.

Since I still need to use the coolant expansion tank with a turbo radiator, I might source my line from here instead of the other head since the other head is pretty crowded with the oversized oil drain.

[kimokalihi]

You're running a coolant line to the tank or to the turbo from there?

[wtdash]

If that's a USDM EJ25D, that should be the EGR port.

From a '96 EJ25D:



TD

[__TT__]

Just plug it. The plug size is M16 x 1.50

[93forestpearl]

Thanks for the pic, wtdash. That makes perfect sense as to why it is open. Also, _TT_, thanks for the thread size. I would have had to dig through boxes of bolts to find something to match.




The next question is, can I plug the turbo feed (oil cooled turbo) and the associated bung on the coolant expansion tank, and be ok. My only question is can I weld that bung shut without upsetting the brazing of the bung.

[__TT__]

Do you have the ability to weld aluminum?

Even if so I would still tap the feed then plug itwhile the block is out. You never know if your gonna need that for something down the road.

[Legacy777]

The next question is, can I plug the turbo feed (oil cooled turbo) and the associated bung on the coolant expansion tank, and be ok. My only question is can I weld that bung shut without upsetting the brazing of the bung.

The coolant discharge on the turbo feeds into the expansion tank and that feeds into the line going back to the suction side of the pump. I don't see any issues in plugging the coolant feed on the head that was meant to go to the turbo. If you plug the corresponding bung on the expansion tank the only coolant supply to that tank would be the line coming off the turbo radiator.

That setup "should" be alright. The only thing that kind of concerns me is the fact the supply & return lines vary quite a bit in size. I don't know if that would create any issue or not where the pump would try and pull more coolant from the tank than the small hose from the radiator could supply. It might start pulling coolant from the overflow. But in theory, that coolant should go back.

I'd probably suggest giving it a try and see how it works. Otherwise, you'd just be running coolant from the head to the expansion tank without really doing any cooling.

[93forestpearl]

Do you have the ability to weld aluminum?

Even if so I would still tap the feed then plug itwhile the block is out. You never know if your gonna need that for something down the road.

I have access to a couple TIG welders, but not at home. However, I did already tap the other head for coolant, since I was originally planning on running my old GT2871R, which needs coolant. Now I'm using a GT3782/4088 VA, so I do not need coolant.





Here is a pic of the -10 oil drain and the coolant line. Real estate is just a little tight. I actually can't thread the coolant fitting in with the oil drain attached, and I can't get at the oil drain fitting with the coolant fitting in, so it is a bit of a conundrum.

The coolant discharge on the turbo feeds into the expansion tank and that feeds into the line going back to the suction side of the pump. I don't see any issues in plugging the coolant feed on the head that was meant to go to the turbo. If you plug the corresponding bung on the expansion tank the only coolant supply to that tank would be the line coming off the turbo radiator.

That setup "should" be alright. The only thing that kind of concerns me is the fact the supply & return lines vary quite a bit in size. I don't know if that would create any issue or not where the pump would try and pull more coolant from the tank than the small hose from the radiator could supply. It might start pulling coolant from the overflow. But in theory, that coolant should go back.

I'd probably suggest giving it a try and see how it works. Otherwise, you'd just be running coolant from the head to the expansion tank without really doing any cooling

I think I would be fine without the line from the head to the tank. The suction from the pump can only pull what it can before the lack of feed will come from the main line. The engine can only hold so much coolant since a liquid is not compressible, so it would not drain the overflow reservoir. Anyways, I'll give it a shot and see where I end up.

[93forestpearl]

Just plug it. The plug size is M16 x 1.50

Any idea on where to find a plug? My usual sources are dry. Fastenal and McMaster-Carr have nothing that works. I would like something with a flange for a copper or aluminum washer. Even a bolt that I could cut off would work.


If all else fails, I could drill it out for 3/8 NPT and use Permatex #2 sealer.

[skid542]

Aircraft Spruce? East Coast Supply (another aerospace vendor)?

It might just be easiest to have a machine shop spin one on a lathe?

[__TT__]

ace hardware

[93forestpearl]

^ I found one at a True Value, but saw them at Ace a couple days later. Finding the right copper washer took a few stops, however.


Anyways, problem solved. Thanks all.

[07Evolved]

all of my experiences tell me that it is an EGR port just like wtdash says...