Thermostat Housing fittings thread size??

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seafish

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While putting Giddyup back together, but before I refill her with HOAT coolant, I have decided that I want to replace as many of the original molded 5/8" heater hoses that I can with high quality but bulk (straight) 5/8" heater hose.

Having already done the viscous heater delete is what makes this even possible and in fact I have figured out a way to route most of the molded coolant hoses more simply by using wide radiuses to make the connections while still avoid moving parts and staying under the engine cover

All that said, it would be easier for me to make one of the cabin heater connections if I could replace the STRAIGHT barbed fitting that threads into the thermostat housing with EITHER a 45 or 90 fitting. These are available readily available in 5/8" barb x 1/2" male iron pipe...there are even a few 90's available with a longer sweep, which is also going to be necessary to make this happen.

The thermostat fitting that I am referring to is the 5/8" straight barb with the hose going to the viscous heater and is also located RIGHT NEXT to the smaller 5/16" right angle barb fitting that connects with the hose to the top of the coolant tank mounted on the firewall.

My questions are--

Is the thread that goes into the thermostat housing on that fitting simply 1/2" untapered make pipe threads or is it some sort of metric equivalent of that??

What is the actual thread size, pitch and taper of that fitting?

Anyone??

TIA
 
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KJowner

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I'd guess it would be BSPT, that's fairly standard on European stuff, it's very similar to NPT but not (officially) interchangeable, it may fit ok but best bet is to take it out and compare it with what you have.
 

KJowner

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British Standard Pipe Taper is its grand title, it's our equivalent to NPT, it has a different thread rate so may not screw in nicely, some sizes are better than others. I work on gas production platforms, the equipment is a mix of British imperial, American imperial and metric, a pain in the rear!
 

lfhoward

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McMaster-Carr sells BSPT to NPT adapters. I know because I used one to plumb propane to my British-made Propex heater in my camping trailer. Maybe you could use that if necessary.
 

seafish

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So I have been able to order an adapter fitting that goes from BSPP to NPT...I am fairly sure that the thermostat housing is BSPP and not BSPT as there is ZERO taper to the existing fitting.

I am thinking that "BSPP" means something akin to British Standard Pressure Pipe and while it has the same thread count and pitch and diameter of BSPT, it uses parallel walls and a flange with seal to prevent leaks Instead of a taper.


 
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seafish

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The cool part of this project is that after I insert the adapter and also install a 1/2" NPT x 5/8" barb 45 degree fitting, then I will actually be able to replace most all of the original and strangely shaped 5/8" hoses (many of which are no longer available at least in the US) that make up the combined engine cooling, cabin heating and also EGR cooling systems of the CRD with simple high quality 5/8" silicone heater hose to make the same connections in longer gentle radiuses.

Will try to post a thread about it with pics after the weekend.
 
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WWDiesel

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Two suggestions, first, use high quality silicone heater hose which is impervious to oil and heat exposure. Second, get rid of the EGR either by total deletion or at least install a block off plate in the exhaust feed line and remove the butterfly plate out of the FCV. The EGR is a know engine killer on this engine and can cause all kinds of issues. The EGR valve is known for failing and sticking parly open allowing backwards leakby and the FCV is known for failure as well and can hang partly shut reducing or limiting air flow/boost into the engine's intake manifold.
 

seafish

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Well the BSPP/NPT adapter fitting that Jeff Bezos delivered was a bust simply because it had regular NPT threads on BOTH ends despite being labeled as BSPP/NPT:mad:

That said, I was STILL able to make this project work because the 5/8"silicone heater hose that I also ordered has a tighter bending radius then regular heater hose!!!

Which, in a way, is even better, since I was able to return ALL of the extra fittings and adapter that I had bought ... and that means lower cost while still maintaining the benefits of future cheaper, easier and more convenient heater hose replacements, as well as the added durability of the silicone heater hose.

ALSO, the way I was able to route the new silicone hoses left more room for the Sasquatch turbo intake hose to be installed WITHOUT pressing against ANY of the other coolant hoses, which can't even be said about the smaller OEM turbo intake hose and the OEM molded heater hoses.

Below are some nice pics, though I still might try to post a better documented instruction thread another time.

Note that the air box is in fact reinstalled in the last 2 pics and that everything fits back together with only minimal contact. That said, I will likely still add more 1" split wire loom between a few of the hoses and also between the air box and the hose right next to it, or maybe just a patch of adhesive heat shield to the air box.

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seafish

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^^^ Closer and closer!!!
Unfortunately I had a painful medical set back that Im currently recovering from... but by next week for sure. :D

Only need to reinstall the battery, change the fuel filter and bolt it back on firewall, refill and burp coolant system with fresh HOAT and, finally, reassemble front end body parts.

That said, I will put off final front end reassembly cuz I am waiting for delivery of the replacement AC condensor/ tyranny cooler that I decided to order. Too many of the fins on mine were corroded and/or damaged for effective cooling.
And I will then prolly replace the accumulator and orifice tube at the same time.
 
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seafish

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Speaking of molded coolant hoses, I was able to source 3 different Gates molded heater hoses that with a little trimming easily served to replace 3 of the OEM molded hoses that are no longer available to me here in the US but that still would have been impossible to replace with the straight 5/8" silicone hose, flexible as it is.

1) Gates #19478 replaces the OEM return hose from the EGR cooler line running across the top of the engine to the OEM "Y" splitter that then joins the EGR return line with the cabin heater return line and combines them to the coolant manifold block below the thermostat. Take the old hose and lay it up against the #19478 and cut off the larger diameter end of the Gates hose so that it almost perfectly matches the OEM one.

2) Gates hose #19035 is a short length 5/8"x 45° molded hose that can simply be trimmed even a little shorter to match the OEM hose running from to the cabin heater hard return line to the same "Y" splitter as the one I described above.

3) This is the 5/8" flexible silicone heater hose that (in conjunction with the viscous heater delete) now runs from the OEM thermostat (housing) directly to the cabin heater inlet.

4) This is the 5/8" silicone heater hose that (in conjunction with the viscous heater delete) now runs from the Y splitter with Hoses 1 and 2 mentioned above to the engine block coolant manifold located under and behind the thermostat housing.

5) ANY Gates 5/8" x 90° molded heater hose (part # unknown, unnecessary and forgotten :oops:) with legs that are at least 6" long and that can be cut shorter to fit the run between the engine block coolant manifold and the thermostat housing.

6) FINALLY the brass barb on the modified thermostat hosing (from LostJeeps member DieselJeepluvr) will connect to to firewall mounted overflow tank with 3/8" silicone heater hose.

I am fairly sure that I am explaining those right??!! ...
You can see them labeled best in these 2 pics --

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