Thermostat Install Problems! (researched, but have question)

Car Nut · Jul 3, 2004

I've read so many posts of people having the same problem I have:

I found that the lower left side of my water oulet was leaking coolant on top of the waterpump. I bought a new gasket, RTV sealer, and a new thermostat.

I installed the items in this order (after lots of cleaning):

1. Applied thin layer of sealant on neck and carefully centered thermostat within the groove (note: the gasket is between the intake and the thermostat). Let dry for 30 minutes.

2. Applied sealant on outer edge of thermostat and around rest of neck area, then pressed on the gasket. Let dry for 30 minutes.

3. Installed the neck (with t-stat/gasket) onto intake, with sealant now on both sides of gasket.

4. Let sit 24 hours. Then drove for 20+ minutes. Stopped and idled twice to check things out.

5. Damn leak still happens, though much much less. Only a drop every few seconds, where before it streamed out.

QUESTION: Should the t-stat be placed on the intake OR should it be placced on the neck??? (I currently have it: neck/sealant/t-stat/sealant/gasket/sealant/intake).

I've tried this twice. My second trip to Advanced Auto Parts resulted in me buying 3 gaskets, just in case (good thing, apparently).

Thanks.

Car Nut · Jul 3, 2004

I cleaned all areas, too, with blade, sandpaper, and it was perfectly clean.

All parts are stock including the neck. T-stat is stock replacement and gasket is just the right size.

AznStanger3v · Jul 3, 2004

you should be resting the tstat on the lower plenum the put the neck over it and tighten. if its such a bother, put RTV around everywhere its leaking. I got pissed off when i saw 2 drops of coolant on my waterpump 5 days after i replaced the timing cover, i put rtv on it and it hasnt even thought about leaking. just a little tip.

1105 · Jul 3, 2004

What I did my last time was stick the t-stat in the housing, put a little bit of RTV on to just to hold it in place (if it got bumped it'd fall out) then put a bead around each hole on the t-stat housing (you know the big one where the radiator hose and the heater bypass hose goes to so each was sealed off) then stuck it on my intake right away... Had the bolts allready stuck through the holes in the housing, screwed them a little into the intake so they would stay, then slowly pushed the housing up to the intake and held it there while I tightned down the two bolts... Only thing I used was RTV (no other gaskets) and I dont have a leak. Other time I did it, I just used a gasket and that was all with no leaks.

My theory why it leaked with the RTV is probably because it hardens (I guess thats what it does) and its an uneven surface so there might be a little weak area where coolant can get by after you tighten the housing down, thats why I stuck mine on right after I put the RTV on it.

Car Nut · Jul 3, 2004

So I should use limited sealant except around lower area and all over the gasket?

Also, use a little sealant to keep t-stat directly on intake. Then I guess I should put the gasket on the intake over the t-stat and then finish it off by putting the neck over the gasket.

I'll try it tomorrow morning and wait less time to get it put back together. However, due to a trip tomorrow, it can sit for several hours before testing it.

SN95Oh · Jul 4, 2004

Somtimes the gasket slips, check that. Ford had to put the thermostat housing vertically... What a b$tch. When I did my thermostat, I just cleaned the surface with a razorblade, wiped it clean with a napkin. put some RTV on my fingure, put a thin layer on the water pump (evenly), stuck the gasket to the pump. Put another thin layer on the housing, held the housing. Then started the bolts by hand. And then tighted w/ a ratchet. Filled with coolant/water, started the car right away and burped it (let air out). Not one leak at all

SN95Oh · Jul 4, 2004

forgot install the t-stat too =)

SN95Oh · Jul 4, 2004

Not water pump... Intake sorry

madams74 · Jul 4, 2004

I place the T stat in the housing and hold in place with the red tacky gasket sealant that is made by Permatex. You can buy it at most parts stores. I then use the same sealant on the intake and place the gasket on it and it will hold in place. Place the same sealant all the way on the neck housing and bolt in place to 18 lbs on a torque wrench. Never had any leaks and I have done this a lot. The Permatex red gasket sealant comes in a can with a nice brush made into the lid. It is the best stuff and I could not make it without it. Go get some.

tistan2 · Jul 4, 2004

Are you sure it is the thermostat housing leaking and not the water pump or the timing cover. My timing cover started leaking in the same spot and I thought it was my housing leaking. If it is the timing cover gasket then it is a good time to put a cam and a new timing chain on.

Car Nut · Jul 4, 2004

I was easily able to see a tiny stream of coolant coming from the left side of the thermostat housing. Actually, I was quite surprised at how easy this leak was to see compared to other leaks that can happen.

I tore off the assembly this moring and it looked like I did a great job. Can't believe it still leaked. I WILL get the red stuff! I've got to buy a new thermostat also, because there is just too much dried sealant on this one. Only $4 so no big deal.

I don't understand how anyone could attach the t-stat to the intake followed by everything else. Not only is it vertical, but there is no groove for it to rest in (but there is a groove in the housing, which seems like it should go there).

94_302 · Jul 4, 2004

I had the same problem but then I went ahead and got the gasket from nappa, the one that one side is sticky. Then I did it again and no leaks since.

FordStang · Jul 4, 2004

i had a coolant leak problem when i was running a FMS Chrome waterneck. Heard they warp so instead of fixing the neck on a machine so it wasnt warped anymore, i figured i just buy a new Factory waterneck. Let the car sit for like 3 days for everything to dry, hasnt leaked since....Knock on wood

Car Nut · Jul 4, 2004

I finally put it back together this evening, so we'll see what happens when I test it on Tuesday or Wednesday (yes, I'm going to let it sit for a while). I did use the "red RTV stuff" and lots of it, especially on the bottom end. Didn't use so much that it will clog any holes, but more than before.

As others recommended, I installed the t-stat in the housing with a thin layer of sealant to keep it in the groove, then immediatley spread sealant all over the rest of the housing followed by the gasket. Then I covered the othe side of the gasket and carefully placed the housing/t-stat/gasket combo on the intake. Bolted it up evenly and snug. I could see a small bit of sealant coming from all around the seal, so it seems consistent.

Thanks again. I'll post if it doesn't work OR just have a local shop do it and replace all the hoses while I'm at it.

Car Nut · Jul 9, 2004

RESULTS FROM FIX:

I fixed the coolant leak from the thermostat area using the steps above. However, after rinsing the affected area real good with water, a couple days later I found a very small trace of coolant puddling in two areas, BUT definitely not coming from the T-stat.

One leak is just to the left of where the original leak was (directly under the small bypass hose and some other small hose). It is really hard to see without a flashlight, but appears to be only a small puddle that doesn't fill up and overflow. (Took two 1 hour trips today at 60mph and with A/C)

Second leak is in the right-most area above the water pump. Definitely not the water pump. Appears to possibly come from lower intake area, but again....difficult to see. As with the first leak, there is only a very small amount of coolant.

Should I worry? The amount lost cannot be noticed in the overflow tank. It really is a small amount.

94GTLaserRC · Jul 9, 2004

Sorry Im late with this....are you using the stock water neck? Are you sure it is not cracked anywhere.

YOU SHOULD BE USING THE BLACKPermatex Gasket Maker.!
It may be worth the $10 investment to get the Steel water neck OEM from DAP. You can TQ that baby down REALLY TIGHT. I went throught the same $hit about 2 months ago...took me 3 tries to get it right.
RC

Car Nut · Jul 9, 2004

94GTLaserRC said:
Sorry Im late with this....are you using the stock water neck? Are you sure it is not cracked anywhere.

YOU SHOULD BE USING THE BLACKPermatex Gasket Maker.!
It may be worth the $10 investment to get the Steel water neck OEM from DAP. You can TQ that baby down REALLY TIGHT. I went throught the same $hit about 2 months ago...took me 3 tries to get it right.
RC

I do have the stock water neck and there are no cracks. I used the red high temp RTV stuff and it work better than the black Permatex I used on a previous "attempt to fix this." I even went so far as to take a paper towel and rub it on the underside of the water neck (once I saw the leak) to see if any moisture would show. Nope! The water neck leak used to fill up each gully until overflowing on the right side over and past the waterpump. Now only the last gulley is filled, but not the one's nearest and upstream of the water neck.

Now the leak is in a different area.......slightly. Before, I could see a stream of coolant, but then it was just a few drops from the water neck. Now there is absolutely no leak coming from that area. Is it possible to tighten the stock water neck too much?

There is now no moisture directly under the water neck. There is coolant on the lower gulley to the left (under the bypass hose) and another way over to the right in the gulley above the waterpump (might be coming from right side of lower intake). No coolant/moisture on water pump OR on any part of the pump's gasket.

Car Nut · Jul 9, 2004

94GTLaserRC,

Thanks for posting. I've read all of your previous posts on this same topic and of course, it helped a lot with the initial leak. I may be wrong on the water neck not leaking, but I swear it isn't leaking. The second leak I described verifies that something else is leaking coolant, but that's not good news either. Argh.....

94GTLaserRC · Jul 10, 2004

Car Nut said:
94GTLaserRC,

Thanks for posting. I've read all of your previous posts on this same topic and of course, it helped a lot with the initial leak. I may be wrong on the water neck not leaking, but I swear it isn't leaking. The second leak I described verifies that something else is leaking coolant, but that's not good news either. Argh.....

IM glad you found the other posts, b/c I would hate to put all that back on here. You still didnt answer if you had thet stock water neck on there. On some of the after market ones, the bypass nipple is also notorious for leaking, but Im sure the stock one could go bad as well. Have you checked the integrety of the bypass hose? There could be a small cut in it as well.

If you have to redo it again, I would:

Get the new water neck
Get a new bypass hose
Use the black gasket maker
Have 1 or 2 extra new gaskets handy.

All that stuff should be less than $20.
If you get the water neck, it comes with one gasket also.

RC

Car Nut · Jul 10, 2004

Dude, you get up early on Saturdays!

I do have the stock water neck.

After looking at my hoses and checking my file cabinet, it appears that my hoses are 4-5 years old, so I'm going to go ahead and replace all of them to be on the safe side.

I took a flashlight and spent a while looking at the two areas that contain leaks. It does appear that neither leak is coming from the intake itself.....thank God. The leak to the left of the neck must be from the bypass hose (as you thought), but we'll see what happens with the other.

The leaks are not major by any means, so I'l be patient with it.

Thanks.

Thermostat Install Problems! (researched, but have question)

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