radiator pressure test questions (1 Viewer)

[Howard705]

heat cool cycle of the whole engine. heater control hi opens valve to circulate air through and out as it expands coolant. DO NOT WORRY about it coming out as releasing the cap. EVERYTHING does it. just don't want the spillage as it appears to be a leak. Quite possibly the heater hoses and radiator hoses which are rubber have slightly ballooned up so slightly and it pushes coolant out.

 

[landcruiser3DP]

heat cool cycle of the whole engine. heater control hi opens valve to circulate air through and out as it expands coolant. DO NOT WORRY about it coming out as releasing the cap. EVERYTHING does it. just don't want the spillage as it appears to be a leak. Quite possibly the heater hoses and radiator hoses which are rubber have slightly ballooned up so slightly and it pushes coolant out.

ok. got it. /thanks/.
just on the heat cool cycle please?
i drive or idle the engine. at some point a thermostat triggers a valve to open and the coolant can travel somewhere? then if i “open” the heater control valve (meaning sliding heater control to heat) - does this do something as well?

 

[Tools R Us]

ok. got it. /thanks/.
just on the heat cool cycle please?
i drive or idle the engine. at some point a thermostat triggers a valve to open and the coolant can travel somewhere? then if i “open” the heater control valve (meaning sliding heater control to heat) - does this do something as well?

Heat cycle is exactly that. Fully warmed up, to fully cooled off, idle, short drives, whatever it takes to get it done. Having the heater on for at least some of the run time flushes any air out that maybe in the heaters.

 

[landcruiser3DP]

Heat cycle is exactly that. Fully warmed up, to fully cooled off, idle, short drives, whatever it takes to get it done. Having the heater on for at least some of the run time flushes any air out that maybe in the heaters.

ok. thanks a ton for the help gents.

 

[landcruiser3DP]

hey gents,
a little more help on this please?
looks like i need to do this again. gauge wasn’t secured on the cap and i blew some coolant around. plus i forgot to put the heater control to heat.
anyway, i started at 14.5 PSI (i was going to go to 15 but the pump on the gauge didn’t seem to want to go higher for some reason).
/anyway/ she has dropped to 14 then 13 and now about 45 min to an hour in it is at 9.5. i’m also seeing that both upper mounts are cracked.
radiator has /not/ needed to be topped off and was full to the top when i first opened the rad cap.
do i hose it down, fill it back up then do it again tomorrow morning with the heater control set to on? then clamber around and try to find a leak?!
with one place to be sure to check is where the metal flanges around the plastic at the top...?
THANKS
jonathan

 

[Howard705]

after that long sitting under pressure I'd still crawl under with a light and look for the tell tale tiny streaks where it has leaked around anything. unfortunately you can't tell where you spilled it though. you may just have some clamps loose etc. look closely. remember with 99.9% air out with the pump is a very tiny volume of air getting compressed- so.... a big drop in psi = small leak. any major leaks go down MUCH faster than that- or right to zero . I've always verified HG leaks ( other engines) this method. pull plugs- leave pumped for a very long time - then crank over and look for coolant spitting out plug holes.

 

[landcruiser3DP]

thanks a lot. i’ve been keeping my fingers crossed.
sounds like it would be really worthwhile to really get crawling around to see what i can find as long as i have the pump.
i didn’t get started til just before sundown so i think i need to go out and pull the pump, fill it up and hose it down. then try it again tomorrow. it’s on the street so i don’t think i have much alternative.

 

[landcruiser3DP]

hi gents.

seem to have been able to do this test in a more controlled way.

2:00 PM / 15.5 PSI
3:30 PM / 13.5 PSI
4:30 PM / 13.5 PSI
5:00 PM / 13.0 PSI

i tried scrambling all over to find a leak and did not seem to find anything. took some pics and did see some liquid but it was hard to tell if it was from originally popping the rad cap. i tried to clean everything but of course this is a bit hard to get all the nooks and crannies.

eventually i put a piece of cardboard under the vehicle and absolutely no accumulation over at least an hour.

also, just as a note i opened the gauge cap very very very slowly and let air (i assume) out of the radiator. not much spillage at all upon removing the gauge and adapter. when i cracked the gauge cap quickly somehow the force expels fluid. much better the former than the latter especially for my wallet...

thoughts on these results?

 

[landcruiser3DP]

i tried super hard to clean up at the top but it is hard to know if any of the liquid at the top (super small amounts) is from a leak. similarly there was some liquid underneath but since i didn’t get under there to clean it is hard to know if it was from a leak.

i guess a due test would be next if i see any problems with the radiator holding coolant?

 

[landcruiser3DP]

two more

 

[jatree]

I've seen some people testing through their overflow reservoir or hose going to the reservoir. The FSM (1996) states pumping system to 17.1 psi to check for leaks whereas a functioning radiator cap can open anywhere from 8.5-14.9 psi. Does the reservoir method work because the only outlet from the cap is the reservoir itself?

 

[jaymar]

I put a 16-lb radiator cap on for two days when old lever type fell apart. That was enough to force a leak in a previously secure NEW hose. Still leaking even with new OEM 13 lb cap from Wits End. So I wouldn’t be adding too much pressure.

 

[jatree]

I've seen some people testing through their overflow reservoir or hose going to the reservoir. The FSM (1996) states pumping system to 17.1 psi to check for leaks whereas a functioning radiator cap can open anywhere from 8.5-14.9 psi. Does the reservoir method work because the only outlet from the cap is the reservoir itself?

None of the stores around me are renting (buy then return) cooling system pressure testers.

However I found out that my bicycle pump has an attachment that fits directly into the hose going to the overflow tank. Would pressurizing from the overflow hose work just as well as pressurizing from the radiator cap?

 

[jaymar]

None of the stores around me are renting (buy then return) cooling system pressure testers.

However I found out that my bicycle pump has an attachment that fits directly into the hose going to the overflow tank. Would pressurizing from the overflow hose work just as well as pressurizing from the radiator cap?

Do you want to rely on bicycle pump pressure gauge?

 

[jatree]

Do you want to rely on bicycle pump pressure gauge?

I know it isn't the most accurate thing in the world but I thought it could get me to somewhere b/w 10-15psi to check for leaks.

 

[Tools R Us]

None of the stores around me are renting (buy then return) cooling system pressure testers.

However I found out that my bicycle pump has an attachment that fits directly into the hose going to the overflow tank. Would pressurizing from the overflow hose work just as well as pressurizing from the radiator cap?

Never tried, the outer seal on the cap may not hold enough pressure? Likely better to get a T fitting and some hose and put it into the little bypass hose at the top tank? This will only pressurize to whatever the cap will hold, likely good enough.

 

[jaymar]

I know it isn't the most accurate thing in the world but I thought it could get me to somewhere b/w 10-15psi to check for leaks.

Given that going to a 16 pound cap Caused problems for me, I Would be cautious.
Also, what shape is your radiator in? If old and borderline and ready to blow, Do you want to find that out now? In other words, are you prepared to buy a new radiator? Sure, better to find out in your driveway – – but still, something to consider. I’m replacing all hoses without pressure testing. Mostly because I suspect the old one is about to go. New one sitting in the garage, but I want to do the main seal etc. when I do that, so I’m biding my time. YMMV.

 

[mtlandcruiser]

Given that going to a 16 pound cap Caused problems for me, I Would be cautious.
Also, what shape is your radiator in? If old and borderline and ready to blow, Do you want to find that out now? In other words, are you prepared to buy a new radiator? Sure, better to find out in your driveway – – but still, something to consider. I’m replacing all hoses without pressure testing. Mostly because I suspect the old one is about to go. New one sitting in the garage, but I want to do the main seal etc. when I do that, so I’m biding my time. YMMV.

New wrench hear.
At the end of the day what is the max pressure I can put on this radiator, I just got tool from autozone.
Should I do it with motor off or on?

 

[leonard_nemoy]

 

[CaptClose]

New wrench hear.
At the end of the day what is the max pressure I can put on this radiator, I just got tool from autozone.
Should I do it with motor off or on?

Good question... just keep pumping it up and pay close attention to the psi as you do it. When something blows up, that’s the max amount of pressure.

In all seriousness though, you don’t need to go much past 16-17 psi to find a leak. Just pump it up to 17 psi and let it set for awhile and keep an eye on the meter. If it goes down, give it the fat girl treatment and look for the wet spot. If there is no wet spot... you have a bigger problem. If it stays at 17 psi, you’re good to go.