Working through some coolant issues.

[jackoholic]

Hello folks,

I'm working through some cooling issues on my B4000 at the moment. The issue suddenly presented itself with no prior warning. I was driving through town and noticed that my heater wasn't blowing warm air despite being set well into the hot range. Shortly after that the temp needle climbed high enough to set off the 'check gage' light without actually going into the red zone.

A short time after I noticed this (20 seconds?) the heater started blowing hot air again. The temp needle IMMEDIATELY went back into the normal range. Then began a cycle of hot air, cold air, hot air with the temp needle swinging back and forth with the changes in the heater air.

Got home checked coolant, added some, and burped the system with some instructions I found on here (thanks big jim!). Problem still there but now with check engine light for #6 misfire. There is no fast leak in the system (no coolant under the truck at any time, if even if its a seep its a slow seep?)

Does not overheat at idle only when moving under load. I don't know how old the t-stat is so I decided to replace it just to knock that outta the way. Opened draincock on rad and it its draining very s....l...o...w...l...y. (as in count each drip). LOTS of sediment.

Questions..

1. Anyway to flush the system faster?

2. How likely is a blockage my problem?

Thanks guys

 

[powerranger262]

Weird, I've had the same symtoms in my old F-150, and it was the thermostat.

 

[Original_Ranger84]

Take the lower rad hose off... thats what I did when I broke the petcock off. let it drain then run water with a coolent system flush, then keep flushing it with water untill it comes out clear. then put 50/50 in or whatever your protection preferrence is.

 

[Lrpalo]

If there is that much sediment in the system. put the hose back on fill the system with water after drained and let it warm up to normal temp with the heat blasting to cycle clean water through everything and repeat as necessary. You could have a lot of stuff in the system just waiting to cause a major problem. Then refill with fresh coolant and see where everything is from there.

 

[low-keys89v6]

If it was just fluctuating temps why would you have a miss fire in cyl#6? No doubt the sediment is not good for the system. I agree flush it out. I would rest the CEL and after flushing the system if the CEL comes back I would pull the plug and see whats going on in there. If your low on coolant and none is leaking its going somewhere...imo. good luck.

 

[jackoholic]

If it was just fluctuating temps why would you have a miss fire in cyl#6? No doubt the sediment is not good for the system. I agree flush it out. I would rest the CEL and after flushing the system if the CEL comes back I would pull the plug and see whats going on in there. If your low on coolant and none is leaking its going somewhere...imo. good luck.

Yeah, I'm trying not to think of the implications

There is a slow weep coming from somewhere, I can see it dampening the sides of the oil pan. It must be pretty slow tho, there never is enough to drip on the ground. (feels/smells like coolant.

I added water to the rad in a futile attempt at creating back pressure to ease the draining of the system but no dice. I'm getting like.. 1/2 a cup an hour out of it A pretty shade of pumpkin vomit as well.

I'll pull the lower hose off and stick the garden hose in when I get home to speed things along.

 

[low-keys89v6]

Pumpkin color is rust.....and lots of it. I would flush the system good. Could be a freeze plug allowing air into the system and having the small leek. Check your manual for freeze plug locations (if any) and see if there is one close to the wet area. If you flush the syatem pull the thermo back out. Use distilled water or straight coolant. Tap water is what causes alot of teh rust and corrosion in cooling systems. good luck.