Replacing heater hose nipple @ cylinder head [1990 Q45]

[masoQist]

The left-hand cylinder head has a steel hose nipple on the back side, that connects to one of the heater hoses. This is part code 11041J, part# 14053-60U01, seen on diagram 3, section 111. Mine is corroded, but not yet leaking. Eventually, I think it will leak. I would like to replace it now, but am not sure if this is possible with the engine still in the car. I’m assuming this piece is either pressed into the cylinder head, or maybe epoxied in place. Has anyone ever attempted this? Any suggestions? Obviously, a failed attempt at extracting the nipple will mean removing the cylinder head.

[maxnix]

You mean like the top diagram on LC-7?

Use a brass or staniless steel brush to clean.

[masoQist]

Yes. Top right-hand diagram on LC-7. That's the only mention of it that I see in the FSM. I was thinking if it were epoxied in place, I could maybe break the bond with a MAPP torch and twist/pry the nipple out using a pipe wrench. I'm guessing it's pressed in place. Maybe some member has a junk cylinder head to experiment with?

If no one has any other good suggestions, I will probably clean it up as best as I can, and return it to service. Then if it ever leaks, I'll just plan on pulling the engine out to replace it.

[masoQist]

OK, here’s how I did it....



Here is the steel adapter nipple. It is pressed into a bore in the cylinder head. This one is still serviceable, but I decided to replace all of the coolant lines and tubes while I had the plenum off, and I didn’t want to leave this one out. If there are any G50’s left on the road in a decade or so, I suspect that these will begin failing from corrosion.

First, install a 0.75” ID shaft clamp.

Here is a stainless steel shim I placed to protect the cylinder head:

Use a pickle fork style ball joint separator to un-seat the nipple. I used a 4 lbs. hammer. I think you could easily damage the cylinder head if you get too carried away.

Once it starts to come out, you can gently tap it the rest of the way like this:



Nissan made it easy to install the replacement. There is a pair of M6 threaded holes placed on either side of the nipple bore. I made an installation tool using M6 allthread, a pair of nuts and washers, and some metal pieces with holes carefully drilled.

Finished installation.

[goody90q45]

Nice write up. Having the right tools sure makes it a lot easier.

[Q451990]

Very interesting! Where did you source the replacement part - is it available from Nissan?

Heath

[masoQist]

The part is available from Nissan. Part number is in the first post. I ordered it from IOS. Unfortunately, the part was back ordered, and took about two months to arrive.

This project started when a coolant hose under the plenum started leaking a few days after purchasing the car. It was certainly rewarding to get the top of the engine put back together with all-new everything and have it fire up on the first try.

[Q451990]

Part number is in the first post.

Ahh... so it is... I guess I got discombobulated with all of the pretty pictures.

Heath