loosing coolant thru radiator cap

blk88lx · 04-10-2004, 12:15 PM

I was working on my car the other day when I noticed coolant leaking out the radiator cap. as a quick fix, I replaced with one from my 5.8 powered truck (my 93 has a 5.8 as well). Both caps were 16 lbs. Drove the car about 600 miles and I noticed when I stopped for gas that there was wetness (green wetness) on the hood above the cap and on my battery (othing pouring out though). Lost a total of 1/2 gallon but no overheating. What gives? The cap off my truck worked fine on the truck.

PKRWUD · 04-11-2004, 04:27 PM

Check and make sure the fill spout on the radiator is flush, and not bent.

blk88lx · 04-11-2004, 09:50 PM

What do you mean by flush?

stang_racer20 · 04-11-2004, 10:32 PM

Even, not crooked

PKRWUD · 04-12-2004, 05:33 AM

Quote:

Originally posted by blk88lx
What do you mean by flush?

Make sure that the top lip of the fill spout, where the cap seals, is perfectly flat all the way across. Use a straight edge if necessary. Often what happens is someone pushes a little too hard when they are tightening the cap, and one edge of the lip gets bent down slightly, making it difficult for the cap to completely seal, or to lose it's seal at a much lower pressure than the cap is rated for. You need to check that lip and make sure it's not bent at all.

Jeff Chambers · 04-12-2004, 06:49 AM

Could be that you've got a head gasket problem and are lifting the 16# cap. First off, check to make sure that the overflow cannister's drain hose is not plugged (blow thru it). Then make sure the hose from the filler neck to the cannister isn't plugged. I had this happen before and blew all the compression out through the cap. Discovered that the hose from the filler neck to cannister was clogged. The excess pressure from blowing compression into the cooling system had nowhere to go but out the cap.

I have also seen the braze between the filler neck and radiator develop a crack. Check there too.

blk88lx · 04-12-2004, 10:31 AM

I'll check all of that. She's on a boat to Europe right now so I'll have to wait till it gets there. Bottom line, even w/the 5.8 I shouldn't need a higher pressured cap?

04-10-2004, 12:15 PM	#1
blk88lx Registered Member Join Date: Jun 2001 Location: Fort Leonard Wood, MO Posts: 179	loosing coolant thru radiator cap I was working on my car the other day when I noticed coolant leaking out the radiator cap. as a quick fix, I replaced with one from my 5.8 powered truck (my 93 has a 5.8 as well). Both caps were 16 lbs. Drove the car about 600 miles and I noticed when I stopped for gas that there was wetness (green wetness) on the hood above the cap and on my battery (othing pouring out though). Lost a total of 1/2 gallon but no overheating. What gives? The cap off my truck worked fine on the truck. __________________ 93 GT, 5.8 EFI usual bolt ons, 3.55's, subs, hurst, K+N 78 F100 Short bed, 5.8, dual pipes 4 bbl 03 Sable

04-11-2004, 04:27 PM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Check and make sure the fill spout on the radiator is flush, and not bent. __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

04-11-2004, 09:50 PM	#3
blk88lx Registered Member Join Date: Jun 2001 Location: Fort Leonard Wood, MO Posts: 179	What do you mean by flush? __________________ 93 GT, 5.8 EFI usual bolt ons, 3.55's, subs, hurst, K+N 78 F100 Short bed, 5.8, dual pipes 4 bbl 03 Sable

04-11-2004, 10:32 PM	#4
stang_racer20 Registered Member Join Date: Jun 2003 Location: Wisconsin Posts: 348	Even, not crooked __________________ 92 Mustang GT, 347 Stroker(Forged Steel Crank/Rods-Balanced, Forged Aluminum Dished Pistons), Trick Flow Track Heat Intake, Trick Flow Twisted Wedge Heads w/ Stage 3 port/polish, 80mm C&L MAF, FMS 30# Inj., BBK AFPR, Trick Flow Stage 2 Cam, Trick Flow 1.6R Rockers, BBK E.L. Headers, Flowmaster Cat-Back, MAC CAI, FMS Pulleys, Griffin Alum. Radiator, MSD Pro-Billet Distributor; AOD, Dynamic 3300 Lockup Converter, B & M Super Cooler, B&M Ratchet Shifter; 3:73 gears.

04-12-2004, 06:49 AM	#6
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	Could be that you've got a head gasket problem and are lifting the 16# cap. First off, check to make sure that the overflow cannister's drain hose is not plugged (blow thru it). Then make sure the hose from the filler neck to the cannister isn't plugged. I had this happen before and blew all the compression out through the cap. Discovered that the hose from the filler neck to cannister was clogged. The excess pressure from blowing compression into the cooling system had nowhere to go but out the cap. I have also seen the braze between the filler neck and radiator develop a crack. Check there too. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

04-12-2004, 10:31 AM	#7
blk88lx Registered Member Join Date: Jun 2001 Location: Fort Leonard Wood, MO Posts: 179	I'll check all of that. She's on a boat to Europe right now so I'll have to wait till it gets there. Bottom line, even w/the 5.8 I shouldn't need a higher pressured cap? __________________ 93 GT, 5.8 EFI usual bolt ons, 3.55's, subs, hurst, K+N 78 F100 Short bed, 5.8, dual pipes 4 bbl 03 Sable

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