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overflow reservior won't drain back into radiator

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Old 05-15-2008, 11:11 AM   #1
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overflow reservior won't drain back into radiator

I've been having a mild overheating problem the past couple weeks. What will happen is.....everything will be fine for a couple days, then it'll try to heat on me (210-220 degrees) alittle. I'll let it completely cool down, and check the radiator to find out it's low. I'll fill it back up, everything will be fine for a few days, then the same cycle again.

This happened yesterday. The day before, I had flushed the whole system and put new antifreeze in. I have a 40 mile trip home from work; everything was fine driving to work and going to lunch. On the way home, after about 30 miles, the temp started slowly climbing to the 210-220 range. I got home, raised the hood,but didn't attempt to open the radiator. But I checked the reservoir and it was completely full of my new antifreeze. I waited about 3-4 more hours and let it completely cool, so that antifreeze would go back into the radiator. Not a drop had drained back in.

There are two hoses on the reservoir; a hose from the radiator neck to the bottom of the reservoir, and a hose from the top/side of the reservoir that drains out underneath the truck. I took the cap off the radiator, pulled the reservoir drain hose out from the bottom, and literally blew into it with my mouth and slowly blew the antifreeze back into my radiator through the neck until it filled back up. So that tells me my antifreeze isn't leaking out anywhere.

What the hell is making the overflow not drain back into the radiator???

Last edited by SD44; 05-15-2008 at 11:18 AM.
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Old 05-15-2008, 11:44 AM   #2
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by SD44
I've been having a mild overheating problem the past couple weeks. What will happen is.....everything will be fine for a couple days, then it'll try to heat on me (210-220 degrees) alittle. I'll let it completely cool down, and check the radiator to find out it's low. I'll fill it back up, everything will be fine for a few days, then the same cycle again.

This happened yesterday. The day before, I had flushed the whole system and put new antifreeze in. I have a 40 mile trip home from work; everything was fine driving to work and going to lunch. On the way home, after about 30 miles, the temp started slowly climbing to the 210-220 range. I got home, raised the hood,but didn't attempt to open the radiator. But I checked the reservoir and it was completely full of my new antifreeze. I waited about 3-4 more hours and let it completely cool, so that antifreeze would go back into the radiator. Not a drop had drained back in.

There are two hoses on the reservoir; a hose from the radiator neck to the bottom of the reservoir, and a hose from the top/side of the reservoir that drains out underneath the truck. I took the cap off the radiator, pulled the reservoir drain hose out from the bottom, and literally blew into it with my mouth and slowly blew the antifreeze back into my radiator through the neck until it filled back up. So that tells me my antifreeze isn't leaking out anywhere.

What the hell is making the overflow not drain back into the radiator???
The cap.
Old 05-15-2008, 11:46 AM   #3
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Re: overflow reservior won't drain back into radiator

A bad radiator cap. The gasket around the neck flange is leaking air back into the radiator so you don't have any suction to suck the coolant back in when it cools off.
Old 05-15-2008, 11:47 AM   #4
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by Yogi
A bad radiator cap. The gasket around the neck flange is leaking air back into the radiator so you don't have any suction to suck the coolant back in when it cools off.

lol, could i be so lucky that it's something that simple and cheap?
Old 05-15-2008, 11:54 AM   #5
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Re: overflow reservior won't drain back into radiator

Well, you've got 2 votes here that say it is.
Old 05-15-2008, 01:07 PM   #6
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Re: overflow reservior won't drain back into radiator

its draining into your motor! OH NOES!
Old 05-15-2008, 02:31 PM   #7
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Re: overflow reservior won't drain back into radiator

Bad radiator cap or sealing surface like the others have said.
Old 05-15-2008, 02:53 PM   #8
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by raider600
its draining into your motor! OH NOES!

Nah, no water in the oil or coming out the exhaust.

I bought a new cap during lunch, but man my old one sure looks good and is still strong. Got a feeling it's not the cap.
Old 05-15-2008, 10:47 PM   #9
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Re: overflow reservior won't drain back into radiator

Cap.


Learned that lesson when I was 17. Popped a head gasket cause of that.
Old 05-16-2008, 10:27 AM   #10
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by SD44
Nah, no water in the oil or coming out the exhaust.

I bought a new cap during lunch, but man my old one sure looks good and is still strong. Got a feeling it's not the cap.


Well it's the waterpump.

Got home and let it cool down, then topped the radiator off and got the temp back up. Some of you may have seen my other thread about having a pulley somewhere making a screeching noise, that's the waterpump too. I put the new cap on, yet was still low of water when i finally got home. After looking the topside over real good, I pulled it up on some ramps and looked at the bottom. There is actually a trail that has been washed clean from the diaphram hole in the bottom of the waterpump, down the water pump and dripping on the harmonic balancer. It's a slow weep, not pouring. It actually doesn't leak at all while running, but it starts a couple minutes after shutting it off. I guess it's from the pressure buildup. I shut it off and got back under the truck, and watched it weep, drop after drop, from the diaphram hole onto the harmonic balancer.

Mine is a 95' TBI. Looking closely from the frontside, it really doesn't appear that I'll need to take the alternator or AC loose to get the pump off. I know I'll have to remove the top of the shroud and the fan, obviously. Have any of you changed a pump that's the same setup as mine? What all did you have to take off?

Last edited by SD44; 05-16-2008 at 10:47 AM.
Old 05-16-2008, 11:20 AM   #11
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Re: overflow reservior won't drain back into radiator

Disconnect the neg of the battery
Remove the belt
Losen the alternator and slide it out of the way
Pull the shroud as necessary
Get some carboard to cover the radiator fins
Drain the coolant...
Pull the fan and hoses, might be a good time to replace some...

Other than that. I'm no help!
Good luck

Last edited by Bill Wheats; 05-16-2008 at 11:30 AM.
Old 05-16-2008, 12:04 PM   #12
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Re: overflow reservior won't drain back into radiator

Glad that you found the problem! Good luck with the repairs!
Old 05-16-2008, 12:24 PM   #13
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by Yogi
Glad that you found the problem! Good luck with the repairs!

Wanna come over and help?
Old 05-16-2008, 12:39 PM   #14
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Re: overflow reservior won't drain back into radiator

Ya! Sure! That's what Friday nights are all about.... Changing some one else's water pump!
I would, but I'm trying to avoid lieing to my better half and the only thing she would buy is that I'm out boozing it up with the guys down at the local pickup joint.

Good luck
Old 05-16-2008, 12:40 PM   #15
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Re: overflow reservior won't drain back into radiator

I'm a real good supervisor!

Where are you located?
Old 05-16-2008, 12:40 PM   #16
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Re: overflow reservior won't drain back into radiator

I was having the same problems a few weeks ago and found out that it was that same thing for me. Bad cap and would not suck from the overflow tank. Put on a new cap and then all of a sudden the water pump started gushing out antifreeze.

Fixed the water pump and now my truck runs great. Two weeks ago I wanted toget rid of it, now I love my truck again lol



Matt
Old 05-16-2008, 01:08 PM   #17
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by xtremefour
I was having the same problems a few weeks ago and found out that it was that same thing for me. Bad cap and would not suck from the overflow tank. Put on a new cap and then all of a sudden the water pump started gushing out antifreeze.

Fixed the water pump and now my truck runs great. Two weeks ago I wanted toget rid of it, now I love my truck again lol



Matt
That's why I can't make myself get rid of it. 234,000 miles and still getting around 23 mpg. Drives me nuts the occasional little nit-pick stuff like this that happens a couple times a year, but for the most part you can repair and service these trucks yourself pretty cheaply. The water pump at the Autozone here is only $19.99.
Old 05-16-2008, 01:33 PM   #18
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Re: overflow reservior won't drain back into radiator

I wouldn't recomend a reman water pump. I know 3 people first hand that used them, and within 2 years replaced it again for the same reason. I would suggest a new one unless you plan on getting rid of it soon
Old 05-16-2008, 01:39 PM   #19
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by SD44
That's why I can't make myself get rid of it. 234,000 miles and still getting around 23 mpg. Drives me nuts the occasional little nit-pick stuff like this that happens a couple times a year, but for the most part you can repair and service these trucks yourself pretty cheaply. The water pump at the Autozone here is only $19.99.
Have you ever seen what is involved with replacing a water pump on a Honda? You have to take the timing belt off the camshaft to get to it! And I think that the pump alone costs $85 too!

There's a lot of advantages to this "Old Iron" that we own!
Old 05-16-2008, 01:48 PM   #20
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by LowBravada
I wouldn't recomend a reman water pump. I know 3 people first hand that used them, and within 2 years replaced it again for the same reason. I would suggest a new one unless you plan on getting rid of it soon
A water pump is a simple piece of iron, a bearing or two and a seal. There really is no reason to buy new if you buy a pump from a reputable source/manufacturer.

Oh, and at some point that "new" unit screwed up, so how good are they really if you find a need to replace it?
Old 05-27-2008, 11:11 AM   #21
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by SD44
Well it's the waterpump.

This ended up being a MUCH easier job than I expected. I didn't even need a swivel joint to get to the water pump bolts. I took off the shroud, radiator, fan, and pulley, then just removed the 4 water pump bolts. I had to remove the fan bolts, but they actually screwed out with just a pair of pliers. The hardest part of the job was getting the heater hose fitting out of the old pump; I had to have someone stand on the pump while I used a wrench and a cheater bar to break it loose.

Did the whole job in about an hour.
Old 05-27-2008, 11:21 AM   #22
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Re: overflow reservior won't drain back into radiator

Quote: Originally Posted by SD44
This ended up being a MUCH easier job than I expected. I didn't even need a swivel joint to get to the water pump bolts. I took off the shroud, radiator, fan, and pulley, then just removed the 4 water pump bolts. I had to remove the fan bolts, but they actually screwed out with just a pair of pliers. The hardest part of the job was getting the heater hose fitting out of the old pump; I had to have someone stand on the pump while I used a wrench and a cheater bar to break it loose.

Did the whole job in about an hour.
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