Leaking coolant

I have a 98 blazer LT. Over the past few months it has been slowly leaking then stopping for a while then staring back. I changed the water pump a while back and it seem to do the trick. Today I was driving home and it started leaking then eventually overheated. I happened to be near an NTB they had a look then told me the problem seemed to be the water pump. I picked up another one and installed it tonight. All done I went to refill the cooant and noticed coolant pouring from the bottom of the truck. I cannot find the location of the leak but if I run the truck for a few minutes steam appears from under the power stearing pump then you can hear steam escaping from the left side of the engine. this leak seems to be pretty bad, and I cannot find it. I would think that with the engine off and just pouring coolant into the radiator the water pump would have nothing to do with the leak. But what do I know? Also There is no heat comming from the vents inside the truck. I am at the limit of frustration with this please if anyone has any idea what the problem is let me know.

Thanks

Hunter

Alright, with such a big leak, this should not be to hard. First, are you sure you installed the water pump correctly, and tightened the hose(s) good? Sometimes the gaskets can slip behind the water pump while your installing it and you get a leak in that area and i will be big. You mentioned by the power steering pump. In that area you have the water pump, and above that your intake gaskets. Highly unlikely, but did you check the freeze plugs on that side of the engine? You have to take a deep breath and focus on that area closely and you'll find it. The system is not that complicatd, and with such a huge leak, its there for you to see.

I rechecked all the hoses and connections they seem to be O.K. I think the overall system is fairly simple. I just don't know why it would be leaking from the left side of the engine when all of the connections seem to be on the right side. Just to make sure I changed the top rad hose. Aside from the leak, there is no heat comming from the vents. I can't help but feel that the two are related somehow.

Thanks again

Hunter

Go to your parts store and get a coolant pressure tester. It'll screw on to your rad where the rad cap goes, and by pumping the hand pump you can pressurize your system manually; this should allow you to find the leak.

Like Blazes said, the cooling system is not very complicated. There's a big hose that goes down to the Tstat, there's 2 hoses going in and out of the heater core, and there's two pathways cast in to your intake manifold. Keep an eye on the lower intake gasket.

Your heat wont work if you are low on coolant. When you find the hole and fix it, then top off the coolant it should sovlve your problem. The heatercore is the first thing that is affected by low coollant.

Thank you all so much for helping me out. I will pick up that pressure tester today and give that a shot. It seem that you all agree that the intake gasket could be the problem. How hard is it to replace if thats the way it turns out?

Thanks

Hunter

If it is comming out that fast it might be a frost plug. Just and idea.

Intake gaskets aren't actually too bad if you do the job right. There are several threads as of late that have had detailed pictures and instructions. I wouldn't rule out anything else though, I only mentioned the gasket for completeness.

I actually just reread your original post... coolant is coming out while the truck is off? Usually coolant only leaks through that lower gasket if the truck is cranking / running. If you're losing coolant while parked with the truck off I'd lean to what others have suggested already (hoses or plugs).

Yes it is true that it leaks while the engine is off. It is the freeze plug that you are refering to? Where would that be in relation to the thermostat?

Does the leak eventually stop after you turn the car off, like after a couple of seconds? It might be your intake, they are notorious for going on these engines. I had it happen to me in April,replaced all gaskets from intake up, but then i mixed coolant with my oil and plugged the oil pump, and so i drove it to the nearest dealership, pulled it in smokin, and told them to give me whatever they could for it. But if you buy a haynes or equivelant repair manual it should be easy to replace intake gaskets, that what I did, hope this helps!

The freeze plugs should be down along the side of the block. About the size of a quarter or fifty cent piece.

Yes it is true that it leaks while the engine is off. It is the freeze plug that you are refering to? Where would that be in relation to the thermostat?

The freeze plug is on the drivers side of the engine block. It looks like a 1 1/2" cap pushed into the block backwards. The purpose of the freeze plug is if your block freezes it pushes the plug out as the water expands, rather then doing damage to your engine block. Did the block freeze on you lately..... ie using water rather then antifreeze?

I am in North Carolina so we don't get cold enough to freeze usually. At any rate I ALWAYS use the proper coolant to water mixture. So I should be good to like -30 or something like that.
this is difficult to describe. Here goes, with the engine off rad cap off, as long as you pour water into the rad the leak continues. OK these are the parts that have been ruled out: Top rad hose to the thremostat. Waterpump (which is what the shop wanted to replace yesterday for just over $500), BTW the leak occured before the waterpump was replaced. As I look at from where I beleave the leak to be comming, I would say it was the waterpump gasket because it looks to be from the same area but I was VERY careful to make sure that the gasket was in place when I bolted it to the engine. Besides it had no affect on the leak. Just so I am clear - Would the intake leak if there is no pressure ie the engine is off and the rad cap is off?

No, the intake probably wouldn't leak if the system wasn't pressurized.

Check those plugs, it doesn't have to be cold to blow those things.

Just out of curiosity, is the rad drain valve closed? It's right beneath the air intake.

I am unsure of the radiator drain valve other than the one on the radiator itself. But right beneath the air intake is the right location.

Take the air cleaner assembly off, pour some coolant in the rad, and look right there. At the bottom of the rad on the driver's side is a white twist valve. When it's not secured your coolant drains out of a hose on to the ground.

Ok I found the leak! And the winner is Lower Intake Gasket!!!(and the crowd roars!!) The coolant pressure tester was how I found it. Picked that bad boy up @ sears last night. Now this presents a new problem.... What is the best way to remove the power steering pump?

Intake gasket is in. Everything back together and it doesn't start. The first thing I thought was a battery problem ( dropping to 5v) still not starting with a new battery, however that is what it sounds like just doesn't turn over. The plug wires are correct but if I unplug the ignition coil the sound doesn't change. So I am wondering if the coil is firing.

Thanks

Hunter

I'm think'n the intake guys, My seems to leak more when the rig is cooled down. when things get up to temp the leak seems to go away. My truck is a 97 with 125K and it is ready to be replaced. if the leak is comming down the back of the engine flowing down the bell housing and dripping near the starter then it is the intake, I think you need to put someone under the thing and see if that is where it is leaking

Jkdon

i doubt this to be you prob but when i bought my blazer it leaked coolant and i found out from pics of guys engines here that the tubes on the overflow were bacwards... the top should be the hose that goes down "the overflow overflow" and the bottom should go up to the radiator

Glad to hear you got the leak man. Now, is your spark good? Fuel pump coming on? Do you hear the starter clicking?

If you changed the intake manifold gasket, you had to take the distributor out.... Did you put it back in correctly?

One tooth off on the distributor does that so find TDC on the #1 piston and then the distro cap and check it. You should hear the fuel pump with the key on run and the fuel rail has a pressure port on that section you took off for the intake.