LB7: Can a bad water pump cause coolant pressure?

[d-max joe]

I keep getting coolant pressure after running truck for awhile. Comes out near water pump after pressure builds up for awhile. When I open cap slowly n pressure drains n coolant rises it will be fine for day or so pending on how hard I drive it. I would like to kno if anyone has ever had coolant pressure from bad pump or broken one?

-I have pulled injector cups n resealed on passenger side.
-Truck is studded so I kinda ruling out head gaskets at the moment.

Before I pull n reseal driver side cups I wanna kno if itcould be water pump?

 

[LBZ]

The leak may be coming from the water pump seal which comes out the weep hole. They normally leak after the engine is shut down. Sometimes it's caused by a worn seal or a plugged rad cap not venting. Normal operating pressure when it gets up to temp can cause this if the seal is bad or the cap is plugged.

If your getting pressure build up long after the engine cools off (hard coolant hoses) then the cause could be over pressure due to a bad gasket or cup.

 

[blk smoke lb7]

There was a theroy on here about w/p's going out when headgaskets started to go (it would take out the w/p seal because over time it would get a little weaker once replaced it would hold the presure and shortly after the headgaskets would blow out)But it is just a theroy.Good luck.

 

[d-max joe]

I switched cap with a buddy and no difference. The motor only has 10k on it with new head gaskets when put back together. I running under 40lbs of boost with stock turbo. So unless the guy who put heads back on didn't torque the studs correct I can't imagine being gaskets. Not saying it its not n I hope not but I gonna pull driver side cups after vacation n go from there.

Just I had someone tell me water pump could be causing pressure and was wondering if anyone heard or seen the same?

 

[Karl Armstrong]

Hi there,
I have the same problem with my sprinter.
It's 2006 415 CDI 906
It was losing coolant due to hi pressure
The coolant was overflowing from the expansion bottle and no heat in cabin
In fact no sign of contamination in the oil nor the coolant brought it to a mechanic
Who told me it looks like a head gasket so he tried to put steel seal( supposedly a head gasket sealer) didn't work
And now I have the van back and I can see with my own eyes that coolant now is dripping from the water pump along with the formula he put in I called him back and told him that now the water pump is leaking he said that even so he still thinks it's a head gasket in fact there's no warning lights coming on to indicate the overheating.
I am lost please help !!!


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[catman3126]

No heat when warm bad pump usually.

Hi there,
I have the same problem with my sprinter.
It's 2006 415 CDI 906
It was losing coolant due to hi pressure
The coolant was overflowing from the expansion bottle and no heat in cabin
In fact no sign of contamination in the oil nor the coolant brought it to a mechanic
Who told me it looks like a head gasket so he tried to put steel seal( supposedly a head gasket sealer) didn't work
And now I have the van back and I can see with my own eyes that coolant now is dripping from the water pump along with the formula he put in I called him back and told him that now the water pump is leaking he said that even so he still thinks it's a head gasket in fact there's no warning lights coming on to indicate the overheating.
I am lost please help !!!



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No heat in the cab is almost always a water pump not circulating. And he is a bad mechanic if he is putting any kind of stop leak in your system. bad idea.

 

[Karl Armstrong]

And now is the gasket been ruined after all that?


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[catman3126]

It could be from over heat if the pump is bad.

 

[Karl Armstrong]

But the van wasn't overheated or there wasn't any warning lights on the dash all it was coolant warning light came on and then was losing the coolant through the expansion bottle valve due to a high pressure the coolant will overflow that's all but now after the steel seal been put into it it's leaking like mad from the water pump I can see it, but the mechanic says even if I change the water pump the pressure will still persist I am really lost



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[catman3126]

what motor is this? I didn't recognize the motor when you first posted about?

 

[Karl Armstrong]

It's Mercedes sprinter 415 CDI 2006


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[catman3126]

It's Mercedes sprinter 415 CDI 2006


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Well what the hell are you doing in a duramax forum man? lmao your in the wrong place buddy. haha

 

[Karl Armstrong]

Look I am lost I don't know what to do or where to go
Please help!!!


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[56taskforce]

If it is overheating then building pressure it could be the pump, but the pressure would not remain after cooling. I would say it sounds as it your pressure is coming from compression, that would point first too head gasket...

 

[Karl Armstrong]

I am sorry to bother you guys I know I am in the wrong place but I am only new to this site and I don't know where to go or what to do


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[catman3126]

Sounds like a head gasket to me also.

 

[ironmax]

I haven't heard many good things about those motors

 

[Max Attitude]

There was a theroy on here about w/p's going out when headgaskets started to go (it would take out the w/p seal because over time it would get a little weaker once replaced it would hold the presure and shortly after the headgaskets would blow out)But it is just a theroy.Good luck.

My head gaskets went years ago at 99k. My water pump is leaking out the weap hole now at 149k. Maybe if you run with bad head gaskets long enough that theory could be true?

 

[Karl Armstrong]

They're full of troubles don't
Buy one


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[Yellow Jacket]

I switched cap with a buddy and no difference. The motor only has 10k on it with new head gaskets when put back together. I running under 40lbs of boost with stock turbo. So unless the guy who put heads back on didn't torque the studs correct I can't imagine being gaskets. Not saying it its not n I hope not but I gonna pull driver side cups after vacation n go from there.

Just I had someone tell me water pump could be causing pressure and was wondering if anyone heard or seen the same?

How much pressure? And if it's leaking from near water pump then it needs replaced anyways.... After it sets for 24 hrs does it still have pressure in upper radiator hose?