Coolent leak

2001 Tahoe 5.3

Have a coolant leak whereas I can't figure out where it coming from. I been noticing several drops on the garage floor every morning for the past few months. The drops are on engine side of the driver side behind the radiator and not near the water pump,weep hole good. I don't see any water hoses on that side of the engine, other than top radiator hose that is in front of the leak. Looking underneath, I don't really see anything. The reservoir is draining a little more frequently now, so I figure it's also leaking while driving. The oil is good and clean, just the usual Vortec oil consumption. I only notice it after the vehicle sits overnight. The vehicle sat in the driveway for a few hours last night after driving and no leak.Any ideas??? Thanks................

2001 Tahoe 5.3

Have a coolant leak whereas I can't figure out where it coming from. I been noticing several drops on the garage floor every morning for the past few months. The drops are on engine side of the driver side behind the radiator and not near the water pump,weep hole good. I don't see any water hoses on that side of the engine, other than top radiator hose that is in front of the leak. Looking underneath, I don't really see anything. The reservoir is draining a little more frequently now, so I figure it's also leaking while driving. The oil is good and clean, just the usual Vortec oil consumption. I only notice it after the vehicle sits overnight. The vehicle sat in the driveway for a few hours last night after driving and no leak.Any ideas??? Thanks................


this may be the radiator tank has cracked or the drain plug needs replacing..remove the covers and inspect the complete driverside plastic tank.

Thanks for the reply Jcat. As said in my thread. The leak is on the driver side behind the radiator, more less under the power steering pump in that vicinity as looking where the drip is on the garage floor and looking up. I did notice what appear red drippage on the bottom of power steering pump lines awhile back but thought it was power steering fluid because no water lines in that area, but have not notice any drippage on the lines lately I was wonder if there is a freeze plug on the block next to the pump, can't see down in there. In regards to your question about the drain plug and radiator tank on the driver side, looked good, no leaks...Any other ideas, Thanks for all your overall input into this forum in the past...

Thanks for the reply Jcat. As said in my thread. The leak is on the driver side behind the radiator, more less under the power steering pump in that vicinity as looking where the drip is on the garage floor and looking up. I did notice what appear red drippage on the bottom of power steering pump lines awhile back but thought it was power steering fluid because no water lines in that area, but have not notice any drippage on the lines lately I was wonder if there is a freeze plug on the block next to the pump, can't see down in there. In regards to your question about the drain plug and radiator tank on the driver side, looked good, no leaks...Any other ideas, Thanks for all your overall input into this forum in the past...


the next area is the water pump gasket. what happens here is the coolant if used with tap/well water or is not replaced often enough etc the metal surface corrodes and these water pumps gaskets leak..then this can run down the power steering pump bracket. tough area to inspect ..

the other item is the temp sensor next to #1 spark plug ...

Jcat, I use a 50/50 mix and have flush it twice since 2002, currently 163,000. I see the temp sending unit that is next to the #1 plug that is screw into the head, it' clean. Though as I said sometimes on the garage floor in the morning, a few drops, a little more than or nothing at all. The area around the pump appears fine. But now that I wasn't paying attention to before on the driver side, I can see at the front of the head next to the power steering bracket, at the base between the head and block I see where there as been accumalation of of whitish/brownish build-up with white drips down the block. Now I am wondering if the head gasket is leaking slowly and most leakage is evaporated on the hot block when operating. Also on a different note I notice that two exhaust manifold bolts have broken off, one in the front and one at the rear of the manifold, any ideas why. The manifold has never been worked on before...Thanks

Jcat, I use a 50/50 mix and have flush it twice since 2002, currently 163,000. I see the temp sending unit that is next to the #1 plug that is screw into the head, it' clean. Though as I said sometimes on the garage floor in the morning, a few drops, a little more than or nothing at all. The area around the pump appears fine. But now that I wasn't paying attention to before on the driver side, I can see at the front of the head next to the power steering bracket, at the base between the head and block I see where there as been accumalation of of whitish/brownish build-up with white drips down the block. Now I am wondering if the head gasket is leaking slowly and most leakage is evaporated on the hot block when operating. Also on a different note I notice that two exhaust manifold bolts have broken off, one in the front and one at the rear of the manifold, any ideas why. The manifold has never been worked on before...Thanks

I am sure you know that this engine has a coolant capacity of 4.5 gallons approx... If the system was flushed you would need to drain out the engine ...that is very difficult..the radiator hose/drain plug only removes about 1.75 gallons. also replacing coolant every 3-4yrs is required with these engines..

you could have a bad head gasket. some have had this occur.external leak ! using some white paper or cloth probe for coolant stains

with your mileage and age you must decide how much to spend..

If it is the head leaking I would try some bars stop leak. use 1/4 of the container and see if it holds..or start breaking down the engine to replace whatever is the cause.

the exhaust manifold bolts do break on these.. especially if the exhaust system has been replaced modified. these bolts are much smaller than the later models..using a reverse drill bit with the manifold still on you may luck out and they will come out..do this with the engine hot...

many exhaust shops have done these bolts ...

Well Jcat, like you said if it's the heads, how much do you want to spend and basically how long do you want to keep the vehicle. Well it was the heads, amaze me because this Tahoe has never overheated. But, I have read alot about this problem with earlier year 5.3's on line. Just a cheap gasket put in my GM. Slow leaks only when cooling down, makes scense now. I ended up just resurfacing the heads. Head shop indicated they were in still good shape unless I wanted to spend more. Replaced head, intake and exhaust gaskets,water pump, oil pump,oil sending sensor, front and rear seals, timing chain kit, cover gasket and every other gasket for this job I didn't mention,and having to tap and drill out the broken off exhaust bolts out of the heads, which is also a common problem as you indicated.The exhaust manifold bolts broke off about 1/4" into the head. Also resurface the exhaust manifolds and replaced all the exhaust manifold bolts with a stronger forged steel bolt. Time wise it was easier to pull the engine, comes out pretty easy. A little engine wear with the rings,didn' mess with it, just didn't want to get that deep into it money wise short of buying a long block. I just want it to run another 50,000 or so. So a little water leak turns into 1400+ job. Well I hope I get the additional mileage out of it. But it runs great, though it ran good before. Just alot of preventive maintenance I guess. Thanks again for your input....

Well Jcat, like you said if it's the heads, how much do you want to spend and basically how long do you want to keep the vehicle. Well it was the heads, amaze me because this Tahoe has never overheated. But, I have read alot about this problem with earlier year 5.3's on line. Just a cheap gasket put in my GM. Slow leaks only when cooling down, makes scense now. I ended up just resurfacing the heads. Head shop indicated they were in still good shape unless I wanted to spend more. Replaced head, intake and exhaust gaskets,water pump, oil pump,oil sending sensor, front and rear seals, timing chain kit, cover gasket and every other gasket for this job I didn't mention,and having to tap and drill out the broken off exhaust bolts out of the heads, which is also a common problem as you indicated.The exhaust manifold bolts broke off about 1/4" into the head. Also resurface the exhaust manifolds and replaced all the exhaust manifold bolts with a stronger forged steel bolt. Time wise it was easier to pull the engine, comes out pretty easy. A little engine wear with the rings,didn' mess with it, just didn't want to get that deep into it money wise short of buying a long block. I just want it to run another 50,000 or so. So a little water leak turns into 1400+ job. Well I hope I get the additional mileage out of it. But it runs great, though it ran good before. Just alot of preventive maintenance I guess. Thanks again for your input....

thanks for your report on the repair ..sounds good...removal of the engine then replacing those other parts with good engine care it should go another 50,ooomi....

the coolant system cannot have any corrosion...some call it voltage in the coolant system..this is when the use of non distilled water and a low concentration of dexcool is used...the aluminum gets eaten much like a prop/ lower unit on a boat.