loosing antifreeze.

ac220 · 12-11-2006, 10:36 PM

Truck ran supper till I had to change the water pump at 150.000 mi. After that , it seems to build pressure in cooling sys. and blows antifreeze out the over flow. Sometimes it would take 500 mi. under a load to do it, and other times it would be less. I had it to a GM dealer and they pressure tested the engine, all OK, no leak down. Spent $500.00 there. Still have the problem. Took it to another diesel shop, and they changed the thermastat, and something to do with the turbo valve, another $500.00, and now it's worse. Now it will spue out coolent at an idle. It now seems that when I haul a load, it will blow out some coolent till it gets down to a point,then the low coolent light comes on , and will run ok till I put more coolent in. Then it will blow it all out again. Both shops said that they believe the heads, and gaskits are ok. I now has 187,000 on it. And have used a lot of coolent to say the least. Now what do I do???

**Tow Master** · 12-12-2006, 01:29 AM

I would have to say there is a air pocket in your motor some where. Usually running it at idle for a while with the rad cap off will burp it but since its on the over flow jug its harder to get out. I think there is a bleeder screw on top somewhere?

I see alot of time there are problems with clogs or air in the heater core.

ac220 · 12-12-2006, 07:13 AM

Yeah, I have bleed out the sys. so many times, and it keeps doinging it, so I would have to believe it's getting air somewhere. I was wondering it the trubo was going bad? Or if the water pump was put on wrong? This all started when the pump was changed.

Kawtipping · 12-13-2006, 01:47 PM

Find a GM medium duty dealer. The guys there would be much better with a Duramax than your local car and light truck dealer. The medium duty guys work on mostly diesels (as opposed to mostly gas at a light truck/car dealer). You said in the last post that the problems started after you replaced the pump..so what brand and where did you get your pump? Did it match the one that came out? Done at a shop, or did you slap it on?

ac220 · 12-13-2006, 02:59 PM

It was a Napa rebuild pump. And it was put in by a indpendent shop. I was wondering if any body had the same problem? My Wife says I need to change the pump again, since this is when it all started.

Kawtipping · 12-13-2006, 04:24 PM

As much as people want to save money on parts, there are some things one should buy from the manufacturer. Water pumps is one of them (at least in my experiences). Having worked at a AC Delco distributor, I have heard all sorts of fun things that have happened with after market parts. An "improved" water pump would not surprise me. I would say spend a little more, get an OE pump from your dealer.

duramaxdavid · 12-13-2006, 07:36 PM

WHats a waterpump cost anyways?

ac220 · 12-13-2006, 08:56 PM

It was $100.00 from Napa for the rebuild.

crashholio · 01-24-2007, 07:02 AM

I had a similar problem with loosing coolant. It had nothing to do with the water pump. I suspect it was related to my pushing the engine too hard before it warmed up.. slightly blew head gasket to one cylinder.. it would pressurize the entire coolant system slightly and push the coolant out enough to make the low coolant indicator come on. dealer fixed it under warranty to the tune of about 5000 buckets and 3 weeks down time the second trip.. the first trip they attempted to change the o-rings on the sleeves that surround the injectors as they go through the head which was not the problem and took 2 weeks to complete. service here sucks

ppfedi · 07-11-2007, 05:30 PM

I read all the posts about waterleaks and waterpumps so I figured I would post. I have a 2001 dura and have been leaking coolant for a few weeks very slightly being a mechanic of 25 years I figured no problem I could not really tell where the leak was coming from so I ordered a waterpump thermostat gskts ect today I tore it down NOT FUN and found the metal tube that connects to the back of the waterpump and goes to the rear of the engine block was the culprit one little oring at the rear of the watertube I would not have found it without taking the waterpump off so I am going to replace it anyway along with the thermostat and bypass hoses I will let you know if I have any problems like the ones you are having with air in the coolant I noticed a bleed screw 12mm bolt head directly ontop of the thermostat housing I would crack that after truck gets to operating temp and see if you get any airbubbles