Thermostat Question

[Gilded_Splinters]

Hello and thanks in advance for your assistance.

I have suspected that my 1989 Cobra 5.7 liter engines had no thermostats in them and I was right.

I ordered thermostat kits and don't think they're right. Somethings not right at least.

The new thermostats are small in diameter...about 1 1/4" I'm guessing and would fall right down into the intake manifold. There is however the usual small block Chevy sized recess in the manifold.

When I turn the thermostat housing upside down, there's a recess toward the top that seems like the smaller thermostat will fit in there, but there's nothing to retain it there.

The exploded view in the manual seems to show the more conventional, automotive style arrangement, but it's hard to say what size the thermostat is in the drawing, and whether it goes up into the housing or down in the intake manifold as I suspect.

I put a pair of thermostats in the were the larger diameter (had 'em in the garage) down in the intake recess and stuck it all together, but have not run it yet. I know that this arrangement is far more complex that an conventional SBC water neck, but will this work, or is this different water flow arrangement requiring something I'm not familiar with?

Thanks!

 

[bruceb58]

Re: Thermostat Question

A big rubber O-Ring holds them in place. There is a groove in the housing for the O-ring. Yes, it fits up into the top of the housing.

 

[Gilded_Splinters]

Re: Thermostat Question

Hmm, there were O rings in the kits...cork rings too and an assortment of gaskets. Some that made sense, some that didn't.

So you're saying that if the housing was upside down on the bench, that thermostat would go in and be retained by an O ring from underneath? That's it? The recess didn't look deep enough, nor did I notice a recess for the ring. That explains why in the diagram, the O ring is underneath the thermostat.

What I'm pretty sure you're saying is that the auto style placement of the thermostats in the intake manifold is wrong. Bummer.

Thanks Bruce.

 

[bruceb58]

Re: Thermostat Question

So you're saying that if the housing was upside down on the bench, that thermostat would go in and be retained by an O ring from underneath? That's it? The recess didn't look deep enough, nor did I notice a recess for the ring.

If you have had a lot of corrosion in the housing, the material that formed that recess may be gone. If that's the case, you need a new housing. I had to buy a new one once because of that.

This is an older housing but it shows how its held in with the o-ring

 

[Gilded_Splinters]

Re: Thermostat Question

I think you're right, and really appreciate the input. That explains the absence of thermostats.

New housings are discontinued I gather.

I guess I'll start hunting around. Where did you find yours?

 

[bruceb58]

Re: Thermostat Question

I guess I'll start hunting around. Where did you find yours?

They are all over the place. Look for part number 3850360. Volvo still uses the same part I believe. They aren't that expensive.

 

[Lou C]

Re: Thermostat Question

I replaced one too about 10 years ago....usually there is so much corrosion in there you can hardly see the rubber ring. You will have to dig out out with a small screwdriver. It actually holds it in there well and at least does not corrode in place. The 'stats should be 160 degree units....