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Discussion Starter #1
I just bought an lly. 2005 Chevrolet 2500hd. When it was at the used car dealership it was leaking out of the water pump. They replaced the water pump and its hose. So I bought it AS IS for tax savings and now its leaking out of the coolant overflow cap tube. It only drops about two inches in the reservoir. Its not enough to trip any alarms but I'm pretty sure its not supposed to be doing that. I've been told if it was head gaskets the upper rad hose would be rock hard when the engine has cooled and sat for a while. Its soft. I have heat and my gauges show no signs of overheating. I bought it from these Ukrainian Russian dealers in NE Philadelphia. They get their trucks totaled or damaged and swap parts from other damaged trucks. Could it be that the reservoir is larger than the original? I dont even know if that was even ever replaced. If it was the cap, would it stop dumping coolant two inches down? It seems to hold pressure in the reservoir cause when the water pump was leaking the salesman unscrewed the cap after a test drive and the coolant came shooting up and out like a volcano sending the cap across the parking lot. If the thermostats were stuck would I still have heat?
 

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There's the possibility that all the air hasn't burped out of the coolant system. These trucks are known to be hard to refill after work on coolant system. My 12 can take a week of driving to get all the air out. Carry a gallon of DeX DeX cool and keep topping off.
 

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They replaced the water pump and its hose.
"It's", as in the lower hose to the radiator, or the crossover, or ....?
There are several.
the salesman unscrewed the cap after a test drive and the coolant came shooting up and out like a volcano sending the cap across the parking lot.
"ew, ew....please work on MY truck!" :rolleyes:


Could it be that the reservoir is larger than the original?
Anything's possible, swapping out parts....but they were the same for several models/years.

now its leaking out of the coolant overflow cap tube.
You've watched it pour out of the surge tank tube,
or you're seeing residue from it leaking after driving,
or you're guessing that's where a leak is (because the surge tank level dropped)?
 

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Discussion Starter #4
There's the possibility that all the air hasn't burped out of the coolant system. These trucks are known to be hard to refill after work on coolant system. My 12 can take a week of driving to get all the air out. Carry a gallon of DeX DeX cool and keep topping off.
I dont think so because its soaking the passenger side tire and ball joints and there was some residual dex in the overflow tube. Im gonna try filling it again and put the overflow tube in a bottle and see if it collects in it. It only does it when I'm driving. You can see its been spraying on the bottom of the truck from moving.
 

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LHN...We ARE the Joneses
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I dont think so because its soaking the passenger side tire and ball joints and there was some residual dex in the overflow tube. Im gonna try filling it again and put the overflow tube in a bottle and see if it collects in it. It only does it when I'm driving. You can see its been spraying on the bottom of the truck from moving.
Well that answers some of the ?s I had. Instead of the bottle idea, Wrap a shop towel around the short overflow tube, see if it gets wet, verifying that's where it's leaking from.

Back to the WP hose mentioned, the lower Rad hose is a complex multi-hose item, not just one big hose going to the radiator.

See pic, the pass side spray may stem from it or the clamps.
The joints in the hose could also be a leak source.
 

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The surge tank should only be filled to line on side (full - cold, or full - hot). If you can't see them go halfway - where seam is on tank. A "full" surge tank is going to blow out the expanding dex.
 

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Discussion Starter #7
The surge tank should only be filled to line on side (full - cold, or full - hot). If you can't see them go halfway - where seam is on tank. A "full" surge tank is going to blow out the expanding dex.
Yeah, I'm only filling it to the line on the tank. It drops exactly to the seam. I couldn't find a bottle. I used a dry rag to see if it was getting wet. I took it for a spin and it dropped and tripped the low coolant on the instrument/gauge panel. The rag got damp, not exactly sopping wet- maybe its coming out as a vapor? The cap doesn't have any kind of dex build up or signs of dry rot. Before this truck I owned a chevy 6.5 and a ford 7.3 before that. Im familiar with working on diesels but ive never had coolant issues besides thermostats. And when the thermostats went on the 6.5 it never forced coolant out of the overflow. Ive read on other forums that when people had the same issue it ended up being the thermostats or head gaskets. The truck has 160k. Completely stock. Im gonna keep filling it to the cold line hoping its circulating, working the air out but its already been driven over 150 miles since the water pump change. Truck seems to run a drive fine. Its a million times stronger than the 6.5. Way better accelerating
 

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If it was a thermostat issue would I have heat?
Sticking open, not much heat.

Might want to either clean or replace the surge tank cap. ($10)
 

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Discussion Starter #10
Well, thanks for your replies. I'll try replacing the cap on Monday and let you know how it goes.
 

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Discussion Starter #11
I was inspecting the cap and noticed something loose inside it. Theres a hole in the middle of it - looks like a keyhole almost. Theres a small spring freely floating around inside there I bet is supposed to be stationary. I found out the cap actually releases excess pressure in the tank hence why its a "pressure cap". When it doesn't release the pressure the coolant rises to the top of the tank and out the overflow. First thing I noticed was tool marks like someone was trying to pry it apart. The o rings seem ok so I originally didn't think it was the cap, and its clean but the cap was full of coolant and that spring is loose inside there. Wont know till Monday. Sort of a relief but its gonna be eating at me all weekend. Wish I could find some way to disassemble it but I guess someone else already attempted that path
 

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Discussion Starter #13
It was the cap. Bought a new one for $14. It started getting real bad on Sunday. Before it was just vapor but Sunday afternoon it started pouring out. I couldn't even make it a 100ft without the tank completely emptying out. I just wonder why someone would purposely break the cap. Mechanics trying to get more work? Fckn odd. Fixed that then found out the transmission fluid is overfilled. Checked it cold and its filled past the hot mark. But thats for another thread i guess.
 

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:neener
 

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Discussion Starter #15
Its a hg. The sneaky russian motherfuckers broke the cap so it wouldn't hold pressure and show signs blown head gaskets.
 
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