When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I’ve heard a lot of talk with people saying when ordering a thermostat (motorcraft) to take the rubber seal off before installing.
is this true? Why would an OEM part come with the rubber seal around it, just for it to be taken off? Why wouldn’t it come with directions stating that it needs to come off? Thank you
the rubber seal I’m talking about is in this picture below
On the 6.9 it won't physically fit into the hole with the rubber ring on it. The rubber ring is for the 7.3, the 7.3 might not even take the gasket, I can't remember on that one but I know you do have to remove it or it won't fit on the 6.9
I don`t remember reading about removing the rubber seal.
But, a couple years back my water pump took a dump.
Being winter and cold and Iam a wimp, I took it to a shop.
I had a motorcraft thermostat for a while I was eventually
going to install. Gave it to the shop to install with the WP job.
Some time later, weeks or months don`t remember, but the
engine just was not warming up + no heat in the cab.
Removed the radiator cap checking things out, and there was
this piece floating in there.
Pulled the thermostat housing, and the other piece of the rubber
was stuck inside the thermostat not letting it do it`s job.
Removed the rubber and reinstalled the stat and is working now.
Have heat.
Now maybe the mechanic installing the stat squished the rubber
bolting things down? IDK.
Then why would the 6.9 and 7.3 be different? Were there 2 different
part #`s in the early days of these trucks? And now just narrowed it
down to just the one part #?.
I don`t remember reading about removing the rubber seal.
But, a couple years back my water pump took a dump.
Being winter and cold and Iam a wimp, I took it to a shop.
I had a motorcraft thermostat for a while I was eventually
going to install. Gave it to the shop to install with the WP job.
Some time later, weeks or months don`t remember, but the
engine just was not warming up + no heat in the cab.
Removed the radiator cap checking things out, and there was
this piece floating in there.
Pulled the thermostat housing, and the other piece of the rubber
was stuck inside the thermostat not letting it do it`s job.
Removed the rubber and reinstalled the stat and is working now.
Have heat.
Now maybe the mechanic installing the stat squished the rubber
bolting things down? IDK.
Then why would the 6.9 and 7.3 be different? Were there 2 different
part #`s in the early days of these trucks? And now just narrowed it
down to just the one part #?.
Charlie
When you remove the thermostat housing there is a step down machined into the block, it fits the thermostat perfectly if you take the rubber off. With the rubber on it sits on top of the block part and doesn't seem right to me. When I did mine the first time I didn't like how it sat and threw the rubber part over my shoulder. No issues since and I've done plenty of them without.
At the time I had a friend with a 7.3, he did his with the rubber and it fit. I can't recall for sure but I think on those the rubber is the gasket...
I have a 87 6.9 out in the shop with 149K miles I picked up for $250 along with the turbo set up.
Next time Iam out there I`ll pull the Thermostat housing and see how that one is installed.
Rubber or no Rubber.
I have a 87 6.9 out in the shop with 149K miles I picked up for $250 along with the turbo set up.
Next time Iam out there I`ll pull the Thermostat housing and see how that one is installed.Rubber or no Rubber.Charlie
Charlie, I keep an extra thermostat "in stock". I just looked and it has the rubber around it plus the regular gasket is in the box. I bought it from an IH dealership and told him it was for a 7.3.
Charlie, I keep an extra thermostat "in stock". I just looked and it has the rubber around it plus the regular gasket is in the box. I bought it from an IH dealership and told him it was for a 7.3.
When I bought mine, I purchased it from the Dealer in Santa Cruz, Ca.,
Told him it was for a 86 6.9. It also came with the rubber and gasket.
So IDK why (if it`s true) the rubber should be removed for the 6.9.
Was there a change in the castings between the two engines?
When I bought mine, I purchased it from the Dealer in Santa Cruz, Ca.,
Told him it was for a 86 6.9. It also came with the rubber and gasket.
So IDK why (if it`s true) the rubber should be removed for the 6.9.
Was there a change in the castings between the two engines?
Charlie
So I found this video, although it doesn't show it, he says you can use either the rubber (so you don't have to buy a gasket), or the gasket. The gasket won't fit with the rubber ring installed.
I wouldn't trust just that little rubber ring alone. Doesn't cover much surface area to seal and will allow rust to get between the housing and block.
Most thermostats you buy don't come with the gasket, just that rubber ring.
I imagine even if you cut the gasket out, it wouldn't let it squish the rubber enough and it would end up in your rad like you experienced.
I'll take pictures later today or tomorrow of the step in the block that the thermostat fits perfectly.
I took it to a shop.
Dealer in Santa Cruz, Ca.,
