OK. Just did my second test non-mucked-up test. Came back blue again (See pic)! I know this is not a 100% head gaskets are a good sign, but I will take it. I am still planning on doing the coolant swap tomorrow, a pressure test after that, and then putting in the in-line thermostat mod (I know it is basically double flushing the system). This time while doing the test I took a good look at everything and noticed part of the cap seemed to be melted. Could this have caused my original over-boiling issue? The truck ran in the same 96-99c range during a pure idle as last time. Also, I was able to finally get ahold of the major service records. Aside from the water pump a few years back (2015) and thermostat (being removed anyway), everything is basically original to the truck. I know the old adage is if it ain't broke don't fix it, but is it worth just upgrading everything while I'm doing the thermostat, to begin with?

 

it doesn't hurt to just go entirely new with the cooling system. hoses, connectors, radiator, water pump, cap, etc...

if the fluid stays blue, that means there is no combustion gases in the coolant, which means your block is not cracked and you don't have a leak between the coolant passages and the water jacket.

Next step is to pressure test to find any leaks. it would help to put UV dye is as well during the pressure test and then you can see if there is any leaks more easily, but if pressure doesn't hold, then you are guaranteed some sort of leak somewhere. I'm not sure if you need to flush after using the dye as well.


if you can do the head gasket job yourself, it isn't *that* expensive and you'll have more peace of mind down the road.

 

@discoinfernoOSV that looks more cut or snapped than melted but yes it needs to be replaced. On the inline mod test the thermostat in boiling water, before installing mine was nfg out of the box, it is pretty rare for thermostats to be DOA but it only takes a few minutes to test. As well check all the hoses, while you have it empty.

Once the inline mod is done you will see much better and predictable heating cooling cycles

 

I've been researching the head gasket replacement and planning for it. I expected the combustion test to turn yellow immediately. Even more amazing, the head gaskets on this have never been replaced. They are original to the truck. I didn't know that was possible. Makes me wonder if I should do them preemptively or not. I'd like to wait until October or so before tackling it since I don't have AC in my garage yet, lol. I'll look at the DYE and see what can be done.

Thanks for the tip. I hadn't thought of doing that but makes total sense. Cut, snapped, melted, the cap has damage. That's all I know.

 

Did you run it again, in between first failed attempt and second correct attempt at testing for combustion gases? If so and it passed, yes, now go forward with new cap, flush and other changes you're making. If no, run it until operating temperature, wait until cool off enough to remove cap, immediately install tester and complete test.

Yes, that cap is toast. Believe l mentioned that in my first post.

Good luck.

 

Yep. I ran it correctly twice (the pic of the blue liquid is after the second attempt). I almost couldn't believe it passed the first time. And yes, I do believe you did mention the cap.

 

Sometimes it's just best to start at the beginning, diagnostic-wise. Rule out all of the simple/inexpensive things first, then when those avenues are exhausted...then we dig deeper into the tool box and wallet.

Hope the cap and other changes get you back on the road!

 

I was able to get the pressure test done today. Came back with two hoses leaking, at the T joint with the bleeder and where the small hose connects to the top of the radiator. Both got moved around a little bit when I was doing the power steering pump and given the age of the hoses, it isn't a surprise. Overall, it lost just 1psi (17psi at the beginning and 16psi at the end) during the 20-minute test. There was a pretty consistent drip from the small hose, the leak at the T joint was a lot smaller. I have ordered a new hoses kit, as well as a reservoir and cap from Lucky 8 and a new radiator (Nissens) from Rock Auto to go with the inline mod from Extinct. I am thinking of replacing all of the clip bands (probably the wrong term, sorry) with hose bands that you can use a screwdriver or ratchet on while replacing all of the hoses. All parts are expected this week and I will tackle the job next weekend (assuming there isn't good fishing weather).

 

Having a hell of a time getting the hoses to the heater core off. Anyone know if I can take this hose out (see pic) for better access without screwing things up.

 

That's the SAI hose, it will be very brittle, be careful with it. You mind some value in buying a hose tool kit. They are screw drivers with pointed hooks on the end for getting under hoses and releasing their bond with the mating pipes. Some also come with spring clamp pliers.