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Exhaust gas tester..

wasted wages

wasted wages

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My Furd project I have been working on is showing signs of a blown head gasket or worse...

The truck has sat for 18 years.... It had coolant in the radiator when I cut the hoses off to replace them,, the inside of the thermostat housing was crusty with rust....

here are my observations...

Radiator is brass/copper and needs to be replaced as the PO has apparently soldered the seams on the tanks in spots ....It doesn't leak...but I'm pretty sure it's lived it's useful life. The fact that it has been repaired leads me to believe that this was a previous overheating / overpressure issue...

The water pump looks to have been replaced before it was parked.
The impeller could have rusted off for all I know...but it doesn't leak and still spins fine..

No water in the oil....
No oil in the radiator..

When I start it.. It runs fine ... no smoke.. no white smoke out of the tail pipe at all...

Main problem is,, it builds a lot of pressure and pins the temp gauge....pops the vent cap and blows out water....within about 8-10 minutes of a cold start.

When I top off the water in the rad... I get bubbles while it's running...
My guess is the head gaskets may have corroded from sitting so long..or the water passages are just totally stopped up..

I have heard of some type of tester that you can put on the radiator and it will test for exhaust gas in the coolant....has anyone ever tried one of these ?

Discuss...... :D
 
As much as I hate to send anybofy to AutoZone, they keep them in stock.

And Fluid


Bubble some of the gasses from your cooling system through the detection fluid and CO makes it go from Blue to yellow.

Very reliable method of verifying the presence of exhaust gasses in the cooling system.
 
Did you consider the possibility the cap is not working properly? not releasing when it should, or releasing too early?

wasted wages said:
My Furd project I have been working on is showing signs of a blown head gasket or worse...

The truck has sat for 18 years.... It had coolant in the radiator when I cut the hoses off to replace them,, the inside of the thermostat housing was crusty with rust....

here are my observations...

Radiator is brass/copper and needs to be replaced as the PO has apparently soldered the seams on the tanks in spots ....It doesn't leak...but I'm pretty sure it's lived it's useful life. The fact that it has been repaired leads me to believe that this was a previous overheating / overpressure issue...

The water pump looks to have been replaced before it was parked.
The impeller could have rusted off for all I know...but it doesn't leak and still spins fine..

No water in the oil....
No oil in the radiator..

When I start it.. It runs fine ... no smoke.. no white smoke out of the tail pipe at all...

Main problem is,, it builds a lot of pressure and pins the temp gauge....pops the vent cap and blows out water....within about 8-10 minutes of a cold start.

When I top off the water in the rad... I get bubbles while it's running...
My guess is the head gaskets may have corroded from sitting so long..or the water passages are just totally stopped up..

I have heard of some type of tester that you can put on the radiator and it will test for exhaust gas in the coolant....has anyone ever tried one of these ?

Discuss...... :D
Click to expand...
 
Yep, that tester will spot exhaust gas in the water. I did not know that AutoZone had them.
I always took my vehicle to a radiator shop and they used theirs.
If you have a good radiator shop, don't sell that radiator short. Often it can be made good as new, cheaper than new, and you might have trouble finding a copper/brass replacement.

Sure sounds like a thermostat/water pump problem.
Head gaskets will do the same thing, but if its that bad, you should see other symptoms.
Pull the thermostat, and leave it out for now. Fill the system with water, leave the cap off.
Crank the engine, and watch the water level. When you blip the throttle with the thermostat out, it should suck down some if the pump is working OK.

Its entirely possible that the water pump impeller is corroded away. If I remember right, its cast iron, so it would take a while, unlike some pumps that have stamped sheet metal.
But it could happen.
Replacement pump is probably between $19 and $30. I would replace it even if it were good.
 
PressureTester.jpg
 
cap is brand new....holds good until it pops off....and the hoses are swollen up hard with pressure....there is no stat in the engine...

I don't want to just throw a bunch of parts at it and then end up pulling the heads.... I have another 302 sitting on the engine stand ( used ) that has very good looking bores and bottom end...

I was thinking I would be better off throwing a set of bearings and rear main seal in that motor,,stick in a nice low rpm cam and lifters,,have the heads cleaned up, new water pump,oil pump and stick that engine in the truck....

there are just too many unknowns about the motor that is in the truck now and I don't want to do a bunch of work on that motor and still end up with a rear main seal leak or something like that....I think I would be money ahead to cleanup the motor on the stand and drop that bullet in there.
 
We used to go to a shop that had the emission tester for doing vehicle inspections when we suspected a head gasket or cracked head or block--they put the "sniffer" over the radiator cap opening with it running ,and any exhaust gases detected there indicated a blown head gasket or cracked head or block..

Might as well yank the heads off it and look--if the gaskets were shim steel originals I bet they rotted away at some point and are letting compression get into the cooling system...if you see no cracks,I'd just put head gaskets on it and see if that cures it...if you do see cracks,oh well--at least pulling the engine will be easier with the weight of the heads off it!..
 
that is true.... I figure it may be worth a shot to pull the heads and take a look....

the engine runs really good and I don't see any oil leaks,,,, but after sitting so long, I'm afraid it may just be a matter of time till the rear main leaks or freeze plugs start to let go....

I think I will pull the heads and take a look....If the bores are worn or the water passages are all blocked and rusted...I'll pull the engine.

like you said... it will weigh less if I end up pulling the motor anyway.... :D

Fordum... there are a few radiator shops around town... You can still get a new brass/copper radiator,,, I just have to see what they would charge me to fix up this one I have,,,it may need a core..:dunno:

If its more than 50% of new, I'll probably just swap a new one in..:waytogo:
 
a cooling system pressure tester is not just for caps... there are multiple ways to use it.. you can do as the directions say and pressurize the system not running, you can hook it up and run the vehicle and it will tell you how much pressure is in the system, find leaks, few other non-auto purposes too...

it's a FAR more standard way to check for a blown head gasket than a fume detector...
 
a cooling system pressure tester is not just for caps... there are multiple ways to use it.. you can do as the directions say and pressurize the system not running, you can hook it up and run the vehicle and it will tell you how much pressure is in the system, find leaks, few other non-auto purposes too...

it's a FAR more standard way to check for a blown head gasket than a fume detector...
Click to expand...


and that's what gets me about this whole deal..... if there is enough pressure to pop the cap.....lets say 13 lbs... and the engine is hot...

when I shut it down and it cools off....wouldn't water leak back into the cylinder if the gasket was blown ? I understand that the water would just steam as it hit the inside of the hot cylinder....but over night...the steam would eventually condense back to water...and you should see it on a cold start from the exhaust... I don't have any symptoms like that..

and if compression can go into the water jacket passages...would 13 - 15 lbs of pressure pumped up with a tester on the cooling system be enough to push the water into the cylinder ??

I don't really see a drop in water level in the radiator over night.... and I don't see white smoke out of the tailpipe...:dunno::dunno::dunno:
 
It might pay off to do some more testing before stripping it down..perhaps its something "stupid" that you overlooked...lower hose have a spring in it??..it could have a clot in the block passages or the heads maybe..or a crack in a head thats so small water cant really leak back into the cylinder enough to be detected...usually you'll see the spark plug in the offending cylinder has all its carbon steamed off it or even has a few tell-tale drops of green anti-freeze on it when you pull it out after sitting overnoght...often if enough leals inti the cylinder you'll notice the engine spins over a revolution or two,then binds up some,then cranks normally again,thats the coolant causing it to hydrolock slightly..

I've taken good running engines all apart to install new freeze pugs before swapping one into my trucks as insurance against having to pull the engine out later if they decided to start leaking...more often than not I ended up replacing all of the originals that were in perfect condition!..but if I had not,I'd be sure to have problems later on...(I had a few LEAK that I put in too,that sucked !!:doah:)....

We got many engines runing at the junkyard that sat for 10-15 years and a few had overheating problems,but few turned out to be a bad head gasket --usually it was a crack in the head or block,or somthing minor like a clogged radiator or stuck thermostat,etc...we had one engine with a heat riser that was stuck closed and it would overheat after a 15 minute run down the road,but not if you let it idle all day long..took quite a while to discover that!..
 
It might pay off to do some more testing before stripping it down..perhaps its something "stupid" that you overlooked...lower hose have a spring in it??..it could have a clot in the block passages or the heads maybe..or a crack in a head thats so small water cant really leak back into the cylinder enough to be detected...usually you'll see the spark plug in the offending cylinder has all its carbon steamed off it or even has a few tell-tale drops of green anti-freeze on it when you pull it out after sitting overnoght...often if enough leals inti the cylinder you'll notice the engine spins over a revolution or two,then binds up some,then cranks normally again,thats the coolant causing it to hydrolock slightly..
Click to expand...

Yup....I have experienced that before with a SBC....It locked up so bad in the same spot every morning that it ended up eating the teeth off of the flywheel in that spot....

all the hoses on this truck are new, and this 302 we are talking about spins right over with no evidence of hydro-locking at all.

When I shut it off Sunday night it was overheating and had lots of pressure built up,,,so when I get to work on it this coming saturday...I plan to pull the plugs before I start it, just to see if I can find any water drops in a cylinder....I actually have acess to a lighted bore scope here at work...might be able to look into the cylinders....:D
 
Sometimes a leak down test reveals bad head gaskets better than the usual ways--by putting compressed air in the cylinders via the spark plug hole,you can sometimes see any bubbling at the radiator cap opening much better,since its a lot more pressure than what is normally in the radiator--the compression of the engine is just as strong, but might not be sufficient or steady enough to show up the leak..while your at it you can listen for leakage by the rings & valves by listening at the oil filler cap,and the intake and exhaust pipes...might give you a better idea if its in need of a rebuild or not without tearing it down...
 
I will definitely try that first.....great idea...

In fact.....that just gave me another idea that will prove it....

If I pump in some R-22 into a reclaim cylinder and pressurize it with some nitrogen....and use that instead of the compressed air...

any bubbles coming out of the radiator would carry the R-22 trace with it if it came through the combustion chamber and into the cooling passages..

just hold my electronic leak detector near the radiator cap opening ...:waytogo:
bingo...:woot:
 
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