ok so I have like 600 miles on the new engine I just put in. I initially had zero leaks of any kind. I got up to school, and its been cold (below zero), and in the last week it developed a huge coolant leak. I lose ~1/2 gallon in about 20 minutes of driving.

(no its not a head gasket or other serious problem, its just a massive external leak from somewhere around the water pump)

I dont know whether its the water pump weep hole or a leak at the hose itself where it clamps onto the water pump. I put a lot of grease (from a grease gun) on the water pump outlet so I could get the lower rad hose off easilly in the future if I needed to for any reason. Im thinking maybe the dexcool deteriorated the grease and now its leaking?

It doesnt leak when the engine is cold. So when I let the engine get cool enough to work on it, I start it up and try to look and it doesnt leak, go figure. Where exactly is the weep hole on the water pump? Any pics of it? I suppose I should probably know where it is seeing as Ive built two of these engines. :confuzeld:

SO, how badly does the water pump start weeping if it goes bad? Is it a slow thing? This leak just started randomly one day. Why would it only leak when the engine is up to temp? Im more leaning towards the lower rad hose leaking.

If its the water pump going bad Ill be mad. But I guess it would serve me right; I had the engine out of the truck less than 1,000 miles ago and you would think I would have the sense to replace the original LLY water pump (has 100,000 miles on it) as preventative maintenance, but im a cheap jackass. Preventative maintenance? Whats that.

thanks
ben

my water pump went up at 106,000 miles, FWIW. From what i read, its common for these water pumps to go up right around 100,000 miles.

when mine started leaking, it was leaving about a 2ft x 2 ft puddle underneath of it when shut off, and a steady drip while running

It's not the 1/4" or whatever size it is cross over hose, is it? I've only seen them weep, but if it's beat, could be your culprit...

Just re-read and saw you have it narrowed down to hose or weep hole...

Not a fan of chassis grease on the neck... I think i'd remove it, clean it, and re-attach dry, or with some Permatex or Indian Head... Then it won't ever leak OR come off.

Just did a pump on the Suburban and it was leaking from weep hole...just a little puddle on the garage floor. Definitely wasn't pouring out. FWIW

Probably the bypass hose above the balancer, Ben.

My Water pump went at 110000 miles the water pump is gear driven so it makes since that it only leaks when running. I would need to run my truck around a couple miles to see the leak start. it would not show in the driveway idleing.

Weep hole if i remember is under the pulley to the left..anyone?

good luck i know i prob didnt help much

If its the water pump going bad Ill be mad. But I guess it would serve me right; I had the engine out of the truck less than 1,000 miles ago and you would think I would have the sense to replace the original LLY water pump (has 100,000 miles on it) as preventative maintenance, but im a cheap jackass.
Murphy's law. Certainly sounds like a pump.

Mine leaked along the drivers side of the pump and ran down the front of the oil pan. It was leaking quite a bit, a steady stream of coolant. First noticed it walking back out to the truck at a rest area. Was towing about 15k pounds in 80+ degree weather. Truck was not running hot and did not smell of coolant at all. Called Eric at Merchant and he recommended removing the o-ring on the rad. cap to keep it from building pressure and leaking any worse, while I limped it into a dealer. It would not leak when cold. Only when warm. Went out at about 160k miles.

did my pump a couple weeks ago. started out with small puddle after had been running (only leaked warm, not cold). then progressed to rather large puddle. Finally found it coming out of weep hole on bottom of pump. Weep hole is almost directly behind the lower hose. Took me forever to find it. Keep looking up through different passages with a good light, and you should find it just behind the hose, close to the block.
Would also possibly lean toward the grease you put on the hose. i always either smear some antifreeze on the inside of hose, or a light quick spray of spray silicone on the inside of the hose, and it slips on.
good luck!

Probably the bypass hose above the balancer, Ben.

already checked that. :)

I knew it was a common leak point when I put the motor in so I made extra sure it was good condition hose and tight clamps. Its definitely coming from the water pump or lower rad hose.

ben

haha awesome, sounds like the pump... Like I said, this motor has been in the truck like 600 miles, and now its leaking. I even told myself "stop being a cheap bastard and put a new water pump in it while the motor is out; it has 100k miles on it and it probably wont last much longer"

but no, I didnt listen. And see where it got me. Last time I listened to myself/tried to second guess myself it broke rods and put a hole in my block. Talk about a coolant leak there.

ben

Shit happens, I guess. Go to NAPA and get the pump. Wish you were closer, Id give you a hand.

haha awesome, sounds like the pump... Like I said, this motor has been in the truck like 600 miles, and now its leaking. I even told myself "stop being a cheap bastard and put a new water pump in it while the motor is out; it has 100k miles on it and it probably wont last much longer"

but no, I didnt listen. And see where it got me. Last time I listened to myself/tried to second guess myself it broke rods and put a hole in my block. Talk about a coolant leak there.

ben

Shit happens, I guess. Go to NAPA and get the pump. Wish you were closer, Id give you a hand.


come on Tom you dont wanna swing up here this weekend? :D

Ive only done a water pump with a motor out of the truck so im not sure what to expect, your DIY guide looks very well done though. :cool:

too bad my "spx 6.6 diesel service kit" is at home...might have to beg the dealer to borrow the flywheel holder.

ben

come on Tom you dont wanna swing up here this weekend? :D

Ive only done a water pump with a motor out of the truck so im not sure what to expect, your DIY guide looks very well done though. :cool:

too bad my "spx 6.6 diesel service kit" is at home...might have to beg the dealer to borrow the flywheel holder.

ben

remove the starter and stick a screwdriver or a 3/4" extension through the flywheel, or better yet, get someone to hold the flywheel with a screwdriver through the little inspection port on the bottom of the tranny

quick question. When you unscrew the bleeder valve on the t-stat housing, do you bleed it with the surge tank cap on or off?

quick question. When you unscrew the bleeder valve on the t-stat housing, do you bleed it with the surge tank cap on or off?

Loosen the bleeder, then pour coolant into the surge tank til it starts to leak out the bleeder. Tighten bleeder, and fill surge tank to proper level. Then watch the tank and add coolant as the rest of the air leaves the system.

I added a very small amount of coolant when I got home from doing mine.

haha so today, I just re-bled the air out of it, and It fixed itself. Doesnt leak at all anymore. Go figure?

So the real problem was a loose bleeder screw?


At least it was a cheap fix.

So the real problem was a loose bleeder screw?.

no the bleeder screw was definitely tight. I think what happened is that I put a lot of grease on the water pump outlet, and I think the dex-cool ate the grease, and started leaking. Then it hardened and sealed itself up.

At least it stopped..that is a good thing.

ha ha ha, i love those kind of repairs where it fixes itself

I don't like things that "fix" themselves...