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1995 Dodge Caravan blowing coolant out radiator

Tiny
BIGDOGHANK
  • MEMBER
  • 1995 DODGE CARAVAN
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 133,000 MILES
3.0 engine. New timing, water pump, thermostat, radiator cap. Replaced head gaskets (Felpro gaskets) heads were cleaned but not milled or machined. Still get some bubbling in coolant overflow. After the engine cools, the overflow is still full but there is a lot of pressure released if I loosen the radiator cap, it does not pull the coolant back into the engine when cooling. Had radiator pressure test and system tested for leaks at Pepboys, they could not find any leaks and said the pressure was good, I asked them to check for exhaust gases in the coolant and got blank stares, so I figured they probably didn't know what they were looking at anyway. Do we need to pull the heads again, or maybe a restricted radiator? I do not see any of the hoses collapsing either.
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Friday, March 26th, 2010 AT 12:42 PM

20 Replies

Tiny
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I agree. They didn't know what you ment. As far as the problem, if you replaced the radiator, I would say that isn't the problem. If you replaced head gaskets, I want to say they should be fine, but that sounds where the problem is coming from. Have you checked compression to see if there is a weak cylender?
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Friday, March 26th, 2010 AT 12:54 PM
Tiny
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Hi, The radiator is the original, it was not replaced just the cap. There has not been acompression test done on the cylinders. Also, still no water is oil, or white smoke from exhaust pipe.
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Friday, March 26th, 2010 AT 1:01 PM
Tiny
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Okay, then I do recommend that you try flushing the radiator to see if that is the problem. I misread your post. I was thinking you replaced the radiator. Is the engine overheating at all?
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Friday, March 26th, 2010 AT 1:29 PM
Tiny
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No, it's not overheating, mostly because I make sure it has coolant in the radiator. I have seen it pull some coolant from the overflow when running and the coolant in the engine gets low. But mostly it just keeps the overflow tank full.
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Friday, March 26th, 2010 AT 1:51 PM
Tiny
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Also I am sure it would overheat because the temp gauge starts to wander on the warm side then goes cool again and the heater blows intermittent cool air when the coolant gets low. I can see where it has gone out the overflow.
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Friday, March 26th, 2010 AT 2:22 PM
Tiny
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The one thing that concerns me is the heater working on and off. It sounds like a head gasket, but it could also be an air pocket. Have you tried to bleed the system?
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Saturday, March 27th, 2010 AT 8:38 PM
Tiny
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Hi,
It looks like the system gets low on coolant and it's blows cold air until the thermostat opens. If I make sure it's full the heater works fine. I try to bleed the system but don't know if I'm getting all the air out. It gets low on coolant and I'm back to square one again.
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Saturday, March 27th, 2010 AT 8:49 PM
Tiny
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FYI, what I did when the head gaskets were replaced. Cleaned lock and head with head cleaner and scraped off all old gasket. Made sure that there was nothing left on the gasket surfaces. Placed new gaskets and torqued all the bolts to spec. Also used new intake gaskets. I did not use any hard abrasive on any of the surfaces.
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Saturday, March 27th, 2010 AT 9:29 PM
Tiny
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That makes sense. Any luck finding a leak.
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Monday, March 29th, 2010 AT 9:34 AM
Tiny
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No, I can't find any leaks, no smell inside the vehicle. Can't find any pinholes in the line going to the overflow. I thought maybe it was sucking air from the overflow line but it looks okay. Before I changed the head gaskets it was blowing out coolant real bad, within ten miles it would be bubbling out the overflow. It was leaking compression into the coolant. I changed the gaskets, now it goes 2-3 days before it gets low.
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Monday, March 29th, 2010 AT 11:03 AM
Tiny
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If there is no coolant getting into the oil, no leaks on the outside. The only thing left is it getting burned. Check closely for any white smoke from the exhaust. Also, did you follow the torque sequence and replace the head bolts? Also, did you torque the head bolts as recommended, to one ft lb, and then increase the next time? If you used new head bolts, they can stretch.

Let me know.

Joe
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Monday, March 29th, 2010 AT 11:16 AM
Tiny
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DOn't see any white smoke, I place my hand over the exhaust an smell, it smells lke exhaust. I torqued th bolts down in 3 steps, part way, then a little more and then to spec. Then rechecked them. Followed the torque sequence both removing and tightening. The old bolts looked okay so I reused them. None of them looked stretched.
The radiator has 133,000 miles on it so if I do anything to it I am going to get as new one.
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Monday, March 29th, 2010 AT 11:26 AM
Tiny
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The only coolant I see and where it comes out of the overflow after driving.
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Monday, March 29th, 2010 AT 11:31 AM
Tiny
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Okay, if the only coolant you see if from the overflow, is there a leak there or does it capture the coolant until it is needed by the engine again? Also, it sounds like the heads were done correctly. The three step process is because the bolts do stretch (you can see it). However, as long as you got it to the correct spec / torque, it should be fine. Does it leak from the overflow or just go into it?
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Monday, March 29th, 2010 AT 12:03 PM
Tiny
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The coolant is filling up the overflow and coming out the top. No leaks in the overflow tank.
The engine does not seem to be pulling any coolant back into the engine when it cools off. The tank stays full.
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Monday, March 29th, 2010 AT 12:08 PM
Tiny
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First, I want to thank you for your patiences. If I was there, you could show me in two seconds. However, when doing the via the internet, it takes longer.

As far as the problem, I want you to check the radiator hoses to see if any of them are pinching shut. Check when the engine is both running (hot) and first shut off (hot). Also, let me know if you replaced the waterpump. The radiator is a concern to me, but if the engine only overheats when it gets low, then the radiator (if not leaking) is doing its job. I would hate to see you get a new one only to have the same problem. Maybe try to have it boiled / rodded out. I know where I live, there is a shop that does all my radiator repair work. They charge 40.00 to boil it, rod it out, repair any leaks, and repaint it. They look and work like new when I get them back. I only ever had one problem over the past 30 years I delt with them and they took care of it.

It's just an option for you.

Let me know.
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Monday, March 29th, 2010 AT 1:21 PM
Tiny
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Don't see any collapsing of the hoses, I also revved the engine up and held it there, still no sign of a collapsed hose.
The water pump is new, a while back I also reset the timing belt and looked for leaking around the new pump at that time, found nothing.
The heater went form blowing warm air to blowing lukewarm air while testing.
In the overflow tank I can see a few bubbles then once in awhile if I hold the rpm up it starts to bubble like you would expect to see if you looked into a radiator when the thermostat opened.
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Monday, March 29th, 2010 AT 2:07 PM
Tiny
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I hate to say it (and I could be wrong) but I think there is still a slight leak in one of the head gaskets. The coolant in the overflow shouldn't be bubbling unless it is boiling (overheating) and that isn't the case.
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Monday, March 29th, 2010 AT 11:44 PM
Tiny
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I did notice that yesterday when I saw the wild bubbling, the overflow tank was still cool so it was either sucking in a lot of air someplace or compression.
Guess it's time to get the hands greasy again.
I appreciate all the time you put into this, I know if you had been able to see it, the diagnostic would probably take only a few minutes. I'll let you know how it turns out.
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Tuesday, March 30th, 2010 AT 8:28 AM
Tiny
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Yes, please let me know what you find. Believe me, I learn a lot every day, and I am anxious to get to the bottom of your problem.

Take care and I look forward to hearing from you.

Joe
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Tuesday, March 30th, 2010 AT 10:23 AM

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