Imagine That, Another Cooling System Problem

Robert Crain

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It's been said on this forum many times that it is a sure guarantee that the thermostat housing on your LS will fail in some catastrophic way at some point in time. Mine has-twice. The first time was back when the car had about 100k on it. I got stuck in the middle of nowhere Vermont, far from home and it cost me a small fortune to get that fixed. The housing cracked wide open and left me stranded.

This time, it failed in my driveway but failed in a completely different kind of way. Interestingly, the thermostat housing (the part bolted to the engine) warped and broke its seal to the thermostat cover (the thermostat cover is bolted to the thermostat housing). I can see daylight through the gap. I can't tell if the part that was replaced in Vermont was a Motorcraft part or not. There are no markings stamped into the plastic.

My replacement parts are due to arrive tomorrow. Friday's high temp is supposed to be 16F here in New Hampshire. Nothing is easy on this car.
 
It's been said on this forum many times that it is a sure guarantee that the thermostat housing on your LS will fail in some catastrophic way at some point in time. Mine has-twice. The first time was back when the car had about 100k on it. I got stuck in the middle of nowhere Vermont, far from home and it cost me a small fortune to get that fixed. The housing cracked wide open and left me stranded.

This time, it failed in my driveway but failed in a completely different kind of way. Interestingly, the thermostat housing (the part bolted to the engine) warped and broke its seal to the thermostat cover (the thermostat cover is bolted to the thermostat housing). I can see daylight through the gap. I can't tell if the part that was replaced in Vermont was a Motorcraft part or not. There are no markings stamped into the plastic.

My replacement parts are due to arrive tomorrow. Friday's high temp is supposed to be 16F here in New Hampshire. Nothing is easy on this car.
If it's a Gen 1 V8 Upgrade the housing to the metal Jaguar S-type one made by URO Parts.
https://www.amazon.com/URO-Parts-NCE2247AD-PRM-Aluminum-Housing/dp/B0066QQUEC
 
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If it's Motorcraft there is markings on it. Mine failed after 3 years internally. One of the shoulders inside broke off and the thermostat assembly shifted sideways. I don't know if there is a aluminum version out there for the gen 2. Fortunately it's a pretty easy job to just replace the housing and thermostat although in 16° nothing is easy.
 
I got lucky and mine came replaced already with the metal housing. I suggest upgrading to that to prevent further problems
 
I got lucky and mine came replaced already with the metal housing. I suggest upgrading to that to prevent further problems
I am thinking he has a Gen 2 after seeing his reply and I am not sure if there is a metal one for that. I have a Gen 2 also so if someone knows of a metal one for it please do share the link.
 
Yeah, my car is a 2003. No markings anywhere on the failed piece so I guess the repair shop in Vermont went aftermarket. I got about 60k miles out of it. Now waiting on parts from Tasca and Ford Parts Giant.
 
I humbly come before this forum seeking wisdom and help. Upon removing the leaking thermostat housing, the 9N499 coolant elbow pipe crumbled into pieces right before my eyes. As most of you know, that part is buried underneath the intake manifold. Who in their right mind would design a car with plastic and rubber parts in such a difficult to access area?

Please double-check these part numbers for me:
Elbow pipe: 2W9Z-9N499-AC
Rubber seal between elbow pipe and thermostat housing: W707299-S300
Gasket between elbow pipe and engine: XW4Z-82555-CA
HR1 bolts (4): W500014-S426 ???? I'm not sure if this is correct

I understand that there might be a way to remove and install the elbow pipe without first removing the manifold but involves cutting the two rear HR1 bolts and replacing them with shorter ones??? Can someone walk me through that process and does anyone know what bolts to purchase?

Any help that you can provide is most welcome. Thank you. Rob
 
I used to have all those part numbers.

They are all listed in one of the main cooling system threads. (that really should have been made a "sticky").

First thing you need to do is is get the car into a semi warm garage/shop. If the engine is too cold... the aluminum block could lock onto the bolts... causing them to twist off/snap. This seems to be more true about the intake bolts.

The other option you want to try avoids pulling the intake... but is still a PITA !

The elbow has tabs on the bottom hole, which keeps it in place and from shifting. So that elbow needs to be lifted straight up when removed.

Some people have loosened the bolts and cut the heads off and just replaced with new shorter stainless bolts.

Others managed to get the bolts high enough, and cut the bottom of the bolts off flush with the flange on the elbow.

There's a 3rd way... but it's difficult to describe without pictures... and I'm not sure where those pics are.

The bigger pain... without removing the intake, is the small "double S" shaped hose that should be replaced when doing the elbow. The hose slips on a nipple at the top of the engine block... right behind the elbow. The other end goes to the throttle body.

Without pulling the intake... that hose is a total PITA... even with using forceps and long bent nose pliers.
 

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