Thermostat problems

427SnakeSC · #1 (**permalink**) 08-24-2006, 03:48 PM

I am trying to change the thermostat in my SB. How do you get the thermostat to stay in place, when you are trying to tighten the housing down? Very frustrating! It just keeps moving around and there are leaks around the housing.

*13* · #2 (**permalink**) 08-24-2006, 04:03 PM

I would try installing the gasket over the thermostat with some silicone. let dry then bolt it up.

427SnakeSC · #3 (**permalink**) 08-24-2006, 06:00 PM

Thanks 13, I'll try that, tomorrow.

*13* · #4 (**permalink**) 08-24-2006, 10:17 PM

Hope it works out for ya!

427SnakeSC · #5 (**permalink**) 08-25-2006, 04:27 AM

I think I'll try what you suggested. I'll take the housing off, and silicone the thermostat and gasket on to the housing and put the whole unit back on tomorrow. Thanks again, why didn't I think of that! Duhh!

*13* · #6 (**permalink**) 08-25-2006, 06:45 AM

Because it wasn't friday.

*13* · #7 (**permalink**) 08-25-2006, 06:48 AM

When I installed mine the hose wasn't on. I reached throught the front of the housing & lined it up. I realize that may not be an option for everyone depending on the type of housing you have & if the hose is on or off.

392cobra · #8 (**permalink**) 08-25-2006, 07:00 AM

Hyde,
I was going to suggest the same .

I use a short piece of dental floss to pull back on it thru the housing with the hose off.

427SnakeSC · #9 (**permalink**) 08-25-2006, 08:14 AM

Quote:

Originally Posted by *13*

When I installed mine the hose wasn't on. I reached throught the front of the housing & lined it up. I realize that may not be an option for everyone depending on the type of housing you have & if the hose is on or off.

I tried this the other day, and was not able to keep it in position. I know that this is a NO-NO, but a Cheby is so much easier to do this job!

*13* · #10 (**permalink**) 08-25-2006, 08:21 AM

Chebbie also put the distributor where you can get to it.

427SnakeSC · #11 (**permalink**) 09-01-2006, 04:50 AM

13, I followed your suggestions. It worked perfectly. No more leaks, but I have a new problem. The temp. fluctuates now. It goes up to just past 210, then abruptly drops down to about 170, stays there for awhile then heads up past 210 again. I put a 180 themostat in, thinking maybe I should go with a 160. What do you think?

Dan Stryffeler · #12 (**permalink**) 09-01-2006, 08:12 AM

Think you might be a little low on coolant - the temperature fluctuations might represent some air blowing through the system when the thermostat opens.

But could be wrong...

Dan

wizard · #13 (**permalink**) 09-01-2006, 08:15 AM

Sounds like the thermostat is doing what it is supposed to do as far as opening. I suspect that the thermostat does not have any bypass openings in it so it waits til it comes up to temp, then opens. This will now allow water to flow and as a result you will see a short term temp drop until the system catches up. As far as the 210 goes, it sounds to me like it may be a 210 thermstat, very common these days for new vehicles. I say that because you get the temp drop at 210. If it were a 180, you would see that drop at 180. Did you check the thermstat before you installed it? The temp rating will be stamped somewhere on the unit.
You also said the temp fluctuates, but then only mentioned 1 cycle. Is this the case or does it go up and down repeatedly?
(I have finally solved my own cooling issues and will be posting a lengthy post in the 460 forum over the week-end.
West Coast owners should be interested.)
THIS HOWEVER DOES NOT MAKE ME AN EXPERT!!

wizard · #14 (**permalink**) 09-01-2006, 08:21 AM

I can also agree with Dan (He posted while I was typing) which could also explain the 210 reading. If you have air at the temp probe, my experience has been the reading will be higher than it actually is. If the thermostat doesn't have the pass through holes in it (some do, some don't), it is very easy to trap air. I fill mine with the temp probe removed to bleed off air ahead of the thermostat.

427SnakeSC · #15 (**permalink**) 09-01-2006, 08:46 AM

The thermostat I installed had the temp, 180 stamped on it and it does have one of those tiny relief holes in it. I was thinking it was low in coolant. I filled it as best I could before I went for a ride. I removed the upper rad hose at the thermostat housing and filled it that way. If I use the rad cap, I can only get a small amount in. I will try and see if it can take any more, later. When I took it out yesterday for a short scoot, this rise and fall of temperature happened over and over again. I was only out for about 15 min, and came back as I was concerned about the fluctuating temp. A friend told me it could be a blown head gasget, but wouldn't I notice the oil becoming milky or water blowing out the exhausts?

Dan Stryffeler · #16 (**permalink**) 09-01-2006, 08:53 AM

Do you have a remote filler on the line going to the radiator?

In a Cobra, the radiator is typically below the thermostat, so you will never be able to get the system completely filled using the radiator cap.

Most use either an expansion tank, or remote filler like the Moroso unit that you splice into the hose...

http://store.summitracing.com/partde...5&autoview=sku

- Dan

wizard · #17 (**permalink**) 09-01-2006, 12:07 PM

Doubt it's a gasket. Yes you would see milky oil, fouled water, white smoke (STEAM) etc. I suspect it's air now that you've verified the stat. You need to open up a port in the manifold such as the temp sensor or perhaps a plug if you have one. This needs to be on the top of the manifold ahead of the stat. The stat will catch air even with a tiny hole since it's closed. Runing it and then let it cool off will also work the air to the top but that's an obvious pain in the a$$. Before you look at any other possibilities, you MUST make sure there's no air in the system.

wizard · #18 (**permalink**) 09-01-2006, 12:12 PM

Hey Dan,

I used that exact part when I replumbed mine. Will have pics when I finish the post in the 460 forum.

Good advice.

Dan Stryffeler · #19 (**permalink**) 09-01-2006, 01:42 PM

Howdy Mista Wizard,

I used the Moroso filler for about three years and it worked fine. But decided to go the expansion tank route. I bought a Dove aluminum tank for a big block, cut the thermostat housing off and made a new one for a small block that we welded on. Looks great/works great - how much do I have into it? I don't even want to think about it...

The funny thing is, I catch a lot of flack at car shows with a Dove tank on a small block; usually accused of trying to fool people into believing that I have a big block, (Dove only makes parts for big block engines) - all I was after was the cast aluminum look to match valve covers and air cleaner cover.

Pic is in my gallery, (before it was installed on the car).

Oh well...

Dan

427SnakeSC · #20 (**permalink**) 09-01-2006, 04:12 PM

Thanks guys! If I am able to get more coolant into the system and run it with the rad cap loose, will that let any air in the system escape?