PDA

View Full Version : Thermostat Replacement--gasket sealant or not?


Kweisner
11-27-2012, 12:29 PM
Hi all,

Replacing the thermo on my '07 197TT with 5.7L MCX. Do I use liquid gasket sealer or not? I've had conflicting info on this and am looking for experienced perspectives. Many thanks in advance for your guidance.

mikeg205
11-27-2012, 01:37 PM
I use a bit of sealant because I had some pitting on mating joints on my 1995

jfw432
11-27-2012, 02:47 PM
Same here... Mine was pitted pretty bad. I tried a new gasket first and it leaked like crazy. I had to use a lot of sealant to make it seal up. I guess it depends on the condition of your manifolds.

Kweisner
11-27-2012, 07:15 PM
Thank you guys. . .sealant it is!

Chief
11-27-2012, 07:41 PM
Coat each side of the gasket with gasket sealer

mikeg205
11-27-2012, 07:47 PM
this is how my monifolds looked for my t-stat after I cleaned it up

Kweisner
11-28-2012, 07:31 AM
Again, thanks for the confirmation. I think my old gasket must have had a tiny leak as well. When I pulled the manifold, one of the two bolts came out with a lot of rust dust in the threads. Likewise, the threaded hole was full of fine rust dust (the hole on the right in the picture). So, the good news here is that I pulled it now--otherwise, the bolt may have eventually rusted beyond normal extraction. Lost of WD40 to displace the rust, and back together it goes!

Gert
03-16-2013, 11:49 AM
*Bump*

five months ago, I removed my thermostat due to an never getting warm engine.

Finally got my new thermostat but I forgot where the old one was fitted? It can be mounted in the upper and the lower housing.

It is an MCX year 2004, no closed cooling.

Anyone please?

JimN
03-16-2013, 01:15 PM
*Bump*

five months ago, I removed my thermostat due to an never getting warm engine.

Finally got my new thermostat but I forgot where the old one was fitted? It can be mounted in the upper and the lower housing.

It is an MCX year 2004, no closed cooling.

Anyone please?

You're wasting a lot of gas and losing performance. These, like all other engines, need a thermostat to run the way they were designed. If an engine never gets warm, REPLACE the thermostat, don't remove it.

You need to mount it in the upper housing if it's a marinized engine OTHER than the LT-1.

JimN
03-16-2013, 01:19 PM
Thank you guys. . .sealant it is!

If you use a gasket, and there's no reason not to, coat the bottom, stick it in place and let it sit for about 1/2 hour. Then, put an even layer on the top, place the housing on (preferably with no hoses, to it sits evenly) and press it lightly into place. Thread the bolts in but don't tighten it. Let it sot for about 1/2 hour before tightening them fully and don't run it for a few hours. I had problems with my cars and trucks with leaking at the thermostat and doing it this way cured it.

GoneBoatN
03-16-2013, 04:26 PM
I can't say that I've used it for a thermostat gasket, but the stuff I really like is Aviation Form-A-Gasket. As JimN mentions, I would coat both sides. This stuff never gets hard so removal in the future will not be a hassel. On an older boat, I used it on a leaky riser and it worked great. http://www.all-spec.com/products/80017.html?gclid=CPTskNeIgrYCFcZ_Qgod8T0A9g

Gert
03-16-2013, 05:36 PM
You're wasting a lot of gas and losing performance. These, like all other engines, need a thermostat to run the way they were designed. If an engine never gets warm, REPLACE the thermostat, don't remove it.

You need to mount it in the upper housing if it's a marinized engine OTHER than the LT-1.
You misunderstood me. I removed the thermostat due to the winter and it is freezing over here. So the boat is living in the garage for five months now... :)

Upper housing, it is going to be. Many thanks.
Ice is almost gone now, so time to fire her up soon.

JimN
03-16-2013, 05:47 PM
You misunderstood me. I removed the thermostat due to the winter and it is freezing over here. So the boat is living in the garage for five months now... :)

Upper housing, it is going to be. Many thanks.
Ice is almost gone now, so time to fire her up soon.

I probably wouldn't have "misunderstood" if you had included the part about removing it for winter storage.

Gert
03-18-2013, 05:34 AM
I probably wouldn't have "misunderstood" if you had included the part about removing it for winter storage.
Apologies, my mistake.

What I do wonder, how is the waterflow?

Am I correct if I figure that the thermostat is on the hot side?

Table Rocker
03-18-2013, 09:59 AM
Apologies, my mistake.

What I do wonder, how is the waterflow?

Am I correct if I figure that the thermostat is on the hot side?
Yes, the pill of the thermostat goes in the hot side of the housing and the lid goes on top.