coolant fluctuation

[WSUcowboy]

dumb question.... but should the coolant fluctuate its level at idle and when the rpms are up? I am still pissing coolant out of the overflow and just recently it started not getting to temp then all of a sudden temps come up to ~200 and all is well, then the low coolant light comes on. resevoir is clear and clean and the truck runs like a raped ape. D/S coolant hose is not hard and no funny colored exhaust. any ideas?

 

[sweetdiesel]

Shut the truck off and crack the bleed on the top of the T-stat housing is is straight coolant?

when you open the lid does the coolant want to shoot out after the truck is shut off?

 

[WSUcowboy]

I'm not sure where the thermostat is on this truck, but when the truck is off and you open the cap it is under pressure, but only when its hot.

 

[sweetdiesel]

I'm not sure where the thermostat is on this truck, but when the truck is off and you open the cap it is under pressure, but only when its hot.

T-Stat housing is between the A/C and alternator. There is a bleeder on the housing.

I will take a pic for you,If you need

 

[WSUcowboy]

I'll go look, you want me to check it with the engine off right?

 

[sweetdiesel]

I'll go look, you want me to check it with the engine off right?

if the truck is up to norm op temp & shut off that would be best.

 

[WSUcowboy]

i didnt get a chance to crack the bleeder when the truck was up to temp, but I did crack it before I drove home and quite a bit of air came out before the fluid appeared. I bled the air out of then and refilled the coolant. Drove it home and the truck came up to temp VERY VERY slowly. When it finally got up to temp it did not puke coolant and everything seemed to be ok?

 

[sweetdiesel]

i didnt get a chance to crack the bleeder when the truck was up to temp, but I did crack it before I drove home and quite a bit of air came out before the fluid appeared. I bled the air out of then and refilled the coolant. Drove it home and the truck came up to temp VERY VERY slowly. When it finally got up to temp it did not puke coolant and everything seemed to be ok?

Keep a eye on it.......If temps start to flux it useally means you have hot gas where coolant should be,Hot gas useally means HG

 

[WSUcowboy]

temps never really fluctuate its either below 160 or ~200. once it gets to temp it never changes, no matter how hard i push it or what I am towing....

 

[sweetdiesel]

temps never really fluctuate its either below 160 or ~200. once it gets to temp it never changes, no matter how hard i push it or what I am towing....

Thats good! Maybe you had some trapped air in there?

 

[SBCNX20]

WSUcowboy

I'll be praying for you, that it isnt a Head Gasket ! But it sounds llike trouble to me.

 

[WSUcowboy]

happened again today, on the way to work everything was fine, then on the way home it didnt come up to temp until LONG after it was supposed to, then it shot up to ~ 200 and the low coolant light came on and it had puked it out the overflow. when i got home i loosened the bleeder on the tstat and got solid fluid. WTF is going on here???


oh yeah and the truck has still never run better!

 

[sweetdiesel]

happened again today, on the way to work everything was fine, then on the way home it didnt come up to temp until LONG after it was supposed to, then it shot up to ~ 200 and the low coolant light came on and it had puked it out the overflow. when i got home i loosened the bleeder on the tstat and got solid fluid. WTF is going on here???


oh yeah and the truck has still never run better!

Maybe a bad T-Stat? I dunno it sounds not good to me.

There is a saying that "It always runs best,Before it dies"

Could try pressurizeing the coolant system over night VIA the coolant tank
it might not leak down if there is a small leak though

Could also pull the glow plugs and check for coolant after the tank is pressured up over night

 

[WSUcowboy]

are there 2 t-stats or just one?

 

[sweetdiesel]

are there 2 t-stats or just one?

2

pull the T-stats and put them in a pail of boiling water,If they open they should be good

Carefull the oring on the T-stat like to stick sometimes but FWIW you can purchase just the 0-rings that go around the T-stat if you need

 

[WSUcowboy]

where is the second one?

 

[sweetdiesel]

where is the second one?

They are both under the T-stat housing right where you bled off the system

Dissconect upper hose - leave the black pipe connected to the housing but remove the 2 bolts on the drivers valve cover and them remove the 5 bolts IIRC on the housing

Shop vac is handy

 

[sweetdiesel]

Only your bolts will use probably a 12 mm

 

[WSUcowboy]

thanks! I will prolly do this tomorrow during lunch!!

 

[sweetdiesel]

thanks! I will prolly do this tomorrow during lunch!!

Both thermostats are slightly different.....Make sure you put them in the same way you took them out Good luck


And have some water/dex handy