Block heater elbow removal

[waqas]

My block heater elbow fitting is rusty and I'd like to remove, clean and paint it (POR-15) before I close up the heating/cooling system again. Of course, the correct finish would be to have it re-plated, but I've no time for that.

Does anyone know how this comes off? I've loosened the smaller fitting nut (32mm), but it doesn't seem to want to come off. Do I need to also loosen the larger fitting nut?

I suppose I can always clean/paint it in-situ, but obviously I would prefer to do so on the bench.

[Dave Gallon]

The larger, inner hex fitting threads into the cylinder head. The pipe passes through this fitting and has a shoulder on the inside, actually inside the cylinder head when installed. The smaller hex fitting acts to secure the pipe shoulder against the inner surface of the fitting threaded into the cylinder head. The interface between the pipe shoulder and threaded fitting is where the seal is achieved.

I suggest you stop where you are and retighten the smaller hex fitting. The chances of removing the larger hex fitting from the cylinder head without applying lots of force are slim. Unless the fitting was installed with anti-sieze compound which is unlikely, coolant will have seeped into the threads and corroded the interface. The act of loosening the larger hex fitting will probably cosmetically destroy it. Worse, I have seen the aluminum threads in the cylinder head get torn out with the larger fitting. If this happened, the cylinder head would have to go to a machine shop for repair of the threads.

[waqas]

Thanks Dave, sounds like good advice.
Luckily I hadn't attempted to loosen the larger fitting (I'd already noticed it entered the head directly, so was hesitant and decided to ask).

The main reason why I loosened the elbow in the first place was to rotate it slightly in order to make it face the firewall heater inlet. It was previously pointing in such a way as to cause my heater inlet hose to kink. It was also blocking the removal of my injection pump cold-start air filter.

Two more questions:

• Shall I apply anything (sealer, anti-sieze, etc) to the smaller fitting threads before re-tightening?
• What torque is recommended for the smaller fitting?

Thanks again,

[Dave Gallon]

Hi! First, be cautions about rotating the pipe. When all is new you can, of course, rotate the pipe any direction. While I have never had this problem, I suspect that certain corrosion patterns on the shoulder of the pipe (where it seals against the larger fitting inside the cylinder head) might make it difficult to get a good seal again. If the pipe is loose, you may want to rotate it under outward pressure to insure the shoulder and larger fitting have a smooth mating surface. No sealer is necessary as the water-tight seal is at the shoulder inside the head. A little anti-sieze compound certainly will not hurt but the steel to steel interface of small fitting to the large fitting is usually not a problem to loosen. Without checking the books, I do not believe there is a torque specification for the smaller threaded fitting. It generally does not need to be extremely tight, just enough to stop any leaks.

[wwheeler]

Waqas,

I actually removed mine about three months ago. But I had everything out on that side of the block (injection pump included) and was still one of the most difficult things I have had to do. Too many bad things can go wrong like Dave mentions. There is a thread here somewhere which gives some more tips about removing this elbow that I posted on.

Long story short, I soaked the part with PB blaster for an entire week and ended up using a huge pipe wrench because the flats on the big fitting were gone. The metal on these fittings is softer than normal fasteners. I admittedly got lucky!

Unless the fitting is shot or you are going to pull your head, I would not advise removing this piece.