I have a 1995 Wrangler 4 cyl. 2.5 liter automatic. I was replacing my thermostat and bought a new housing because the old one was corroded. When I put the new thermostat and housing on the engine and poured coolant in the radiator the thermostat housing leaks from the bottom bolt. I cleaned the old gasket and sealant material off of the engine and applied new permetex sealant on both sides of the new gasket. When I tightened the housing and filled the radiator with coolant, I still got the same leak. I also tried using ATV sealant, but got the same results. I tried tightening the bolt to stop the leaking, but I over torqued it and the bolt head snapped. I extracted the bolt and inspected the new housing I had bought. It looked like there may have been a crack in the housing near the leak area, so I returned it to Autozone. I took my replacement thermostat housing, coated the gasket, bolts, and bolt holes with permetex copper sealant, and still get the same leak from the bottom bolt area . Any ideas what I should do next?
Last edited by jeepster1976; 05-31-2010 at 04:46 PM..
Not real sure on the 4 cylinders but if the thermostat sits at a angle alot of times it can drop down and keep the housing from sealing at the bottom.
Use a little RTV on the thermostat itself to hold it in place. It will keep it in place as you install the housing.
93 YJ SOA 2" springs front, XJ springs rear w/main leaf added, High pinon 9 inch rear detroit locker front Dana 44 ARB 4.56 Gears, 36 inch Irok tires too much to list. www.mijc.org
Sometimes things just don't seal up so well, and in those cases you could stand a little help.
Here is my "secret weapon" sealer:
Permatex #3 Form-a-gasket Aviation Sealer
Non-hardening liquid gasket sealant/dressing/coating is a thin, brushable dressing or sealer for close-fitting parts. Suitable for continuous temperatures to 400°F (204°C). Resistant to antifreeze, aviation fuels, high-detergent oils and lubricants. Conforms to MIL-S-45180 D.
Read the list again, yep antifreeze is on there too! You can use it on T-stat housings & radiator hoses that prove to be difficult to seal up at the radiator, heater core, or water pump fittings. This stuff is amazing, it will seal up anything and without dealing with the goopy RTV that I despise so much and NO WAITING TIME!
Just use the "brush-in-can" lid and smear a thin film on both sealing surfaces & put them together & add the fluids/oils/etc. and be on your way. Use it on oil pans, valve covers, automatic tranny pans, case halves or anywhere. It's also a great thread sealer like for drain & fill plugs too. It's Aviation and MILSPEC certified.
Thanks for the tip TSEJEEPERS! That fixed the leak. However, now my engine seems to be running hotter than before even though I installed a brand new 3-core radiator, new heavy duty transmission cooler, new water pump, new thermostat, and new temp sensor. I burped it last night and I saw some funny results. I would see the temp gauge go up to about 215, drop very abruptly to about 130-150, and then rise again to about 215. This sequence repeated itself once more. I did get some permatex copper sealant spray on the temp sensor portion that makes contact with the water. any ideas of what's going on now? I haven't driven it on the street yet. Also, the top hose is hot after running the engine, so water is being circulated through the thermostat.
I replaced my waterpump and resealed my tstat housing about three weeks ago. My temp gauge fluctuated like that for about a week.
Make sure that you keep your overflow reservoir at the proper levels so that it can go through the burp and drink cycle as it is designed. Oh, check that the cap on the reservoir is tight.
Wrenching isn't the problem, it's the brains attached to the hands...unfortunately, I'm lacking some of the former so that's why I'm asking you guys!!
I had to sand the crap outta my head on the housing area to get it to seal correctly. There was so much built up gunk around it, that it didn't seal the first time I replaced the housing. Make sure you have good mating surfaces. Also the housing is very soft aluminum (at least my replacement was) it is easy to over tighten and recrack the housing.
I had the same problem and it is because the stock housing is very thin and warps under through the years of getting hot then cold. It usually doesn't cause you issues until you take it off. Then it won't seal back right. I went on Quadratec and got a replacement housing for $9. Never leaked again.