coolant cap problem

I have a 88 waggy 4.0 and have been having a issue getting a cap to seal on my plastic coolant tank on the pass side firewall. I have replaced it 3 times and even replaced the entire tank as well why in the heck does these caps all leak? My temp hangs in the 190 to 210 range but has never over heated but in the summer it looses a a lot of coolant I'm topping off every week. Any help would be greatly appreciated.

Go to your local Oriellys and get a Stant Volvo recovery tank cap. Its a much better quality than the cheap stock cap. You need to find out why your tank is swelling. You have a leak somewhere.

Picture;

Xjtrailrider has it nailed:

CLOSED SYSTEM RADIATOR CAP UPGRADE: Stant Volvo 740 2.3L style cap for $8.95, #10244.

If "they" don't carry Stant, they can look up the interchange part number.

Cool thank's I'll try the Volvo cap any particular year to ask for?. No leaks other than the cap thats where the coolant is coming from and my tank is not swelling up it's new last summer the cap is losing the coolant after 20 miles or so on a warm day you pop the hood and can hear it hissing and the top of the tank is covered in coolant. I've tried teflon tape but figured there had to be a better fix again thank's I'm going to try the Volvo cap hope this fixes her.

They can look it up for you under the part number--10244:

Volvo7402.3 L 2316 CC L4 SOHC 8 Valve1985 - 1985Volvo740
1986 - 1992Volvo7602.3 L 2316 CC L4 SOHC 8 Valve1984 - 1984Volvo760
1983 - 1983Volvo760
1985 - 1990Volvo7802.8 L 2849 CC V61987 - 1988Volvo780
1989 - 1991Volvo850
1993 - 1997Volvo940
1991 - 1995Volvo960
1992 - 1997VolvoC70
1998 - 2004VolvoC70
2006 - 2007VolvoS401.9 L 1948 CC L4 DOHC2004 - 2004VolvoS40
2000 - 2003VolvoS40
2007 - 2008VolvoS602.4 L 2401 CC L5 DOHC 20 Valve2005 - 2005VolvoS602.4 L 2435 CC L5 DOHC 20 Valve2005 - 2005VolvoS602.5 L 2516 CC L5 DOHC 20 Valve2005 - 2005VolvoS602.5 L 2521 CC L5 DOHC 20 Valve2005 - 2005VolvoS60
2001 - 2004VolvoS60
2006 - 2009VolvoS70
1998 - 2000VolvoS802.5 L 2521 CC L5 DOHC 20 Valve2006 - 2006VolvoS802.9 L 2922 CC L6 DOHC 24 Valve2002 - 2003VolvoS80
1999 - 2001VolvoS80
2004 - 2005VolvoS90
1997 - 1998VolvoV40
2000 - 2004VolvoV70
1998 - 2007VolvoV90
1997 - 1998VolvoXC70
2003 - 2007VolvoXC902.5 L 2516 CC L5 DOHC 20 Valve2005 - 2005VolvoXC902.5 L 2521 CC L5 DOHC 20 Valve2006 - 2006VolvoXC902.9 L 2922 CC L6 DOHC 24 Valve2005 - 2005VolvoXC903.2 L 3192 CC L6 DOHC 24 Valve2010 - 2010VolvoXC904.4 L 4414 CC V8 DOHC 32 Valve2007 - 2007VolvoXC90
2003 - 2004VolvoXC90
2008 - 200

The stock caps have a temperature-plastic and structural design flaw, the ones coming from China. The Volvo cap (seems to be one they have used for decades) works beautifully on the Renix bottles. The black caps are also too tall, the hood hits them and crushes the bottle, making the cap swell, and the walls on the cap are too thin, and not reinfoorced like the volvo cap sides. Get the Volvo cap. There is also another good MOD that Muad'dib came up with for the bottom plastic nipple.

http://www.naxja.org/forum/showthread.php?t=952147&highlight=renix+bottle

I have about 4-5 years on these now IIRC.

I've since switched to the open system since the pic above. I had gone so far as to lower the coolant reservoir bracket to keep it from hitting the hood. That was before i found out about the Volvo cap.

Stock location;


Lowered location; I modded the stock shelf/bracket to lower the tank about 3"

I wonder if Jeep put the bottle up there so as to be the highest point in the cooling system to purge air?

I went with the Volvo bottle and cap. Seems to be a little thinner and quality type of plastic that is far outlasting any of the football tanks I've had.

joe_peters said:

Xjtrailrider has it nailed:

CLOSED SYSTEM RADIATOR CAP UPGRADE: Stant Volvo 740 2.3L style cap for $8.95, #10244.

If "they" don't carry Stant, they can look up the interchange part number.

Click to expand...

New Napa # is 703-1396.

Late to this thread, I will just add that with the stock cap, I found it really critical not to overtighten it. It has a little rubber gasket in it, and if you sock it down hard the gasket distorts and it leaks.

Matthew Currie said:

Late to this thread, I will just add that with the stock cap, I found it really critical not to overtighten it. It has a little rubber gasket in it, and if you sock it down hard the gasket distorts and it leaks.

Click to expand...

I have in a pinch used a worm clamp around the stock cap to keep it tight to the tank.

xjtrailrider said:

I have in a pinch used a worm clamp around the stock cap to keep it tight to the tank.

Click to expand...

X2. After-market tanks and caps don't have very good plastic threads.

The 703-1396 cap, like the one Joe is referring to, seem to work well even on the cheapo bottles.

xjtrailrider said:

I have in a pinch used a worm clamp around the stock cap to keep it tight to the tank.

Click to expand...

I used the worm gear clamp too (it works well on cap issue), before the volvo cap solution was reported, but the hood was still crushing the tank and busting the sidewall over time (like 12 months, one summer and it was toast on the side wall). Some people moved the shelf. I was about to do that when the volvo cap solution showed up. The other OEM tank plastic is better at handling extreme summer heat than the aftermarket Renix bottle plastic IMHO.

I have gotten mine down to a peak of about 210 F at the T-stat in 105 F heat waves here with the AC going at max, crawling in 5 pm freeway traffic for 2 hours. But it took the ZJ clutch and 3 row CSF radiator and finally fixing the real problem, the leaks in the exhaust that were blowing on the engine block, LOL!!!

Much thanks didn't really notice that the hood was hitting the top of the cap but will think of dropping the tank down too. again thank's for the links and info.

No need to lower the tank if you use the volvo cap.

Ecomike said:

No need to lower the tank if you use the volvo cap.

Click to expand...

X2, I wish I had found the cap before i spent 2 hours lowering the bottle shelf.