5.3 vortec coolant leak

I have a 2000 Silverado with the 5.3 vortec v8 I bought with 138k miles on it. I am currently noticing the coolant leak not sure where it is coming from as of yet. It’s is not overheating, oil pressure is good, no coolant in the oil from what I can tell from the dipstick I have not drained it yet. I did have the check engine light come on about a week ago. It was a misfire in cylinder 5. I pulled the plug on that cyclinder and it looked fine. Kinda at a loss for what the problem is. I’m hoping it’s not a head because I’m poor. Intake gasket? Water pump?

Any help is appreciated

The first thing you need to do is an extremely thorough visual inspection

There’s a very good chance you’ll be able to see the problem

here are a few good candidates . . .

water pump

plastic radiator tank . . . I’m thinking of the seams

heater hose connections at the firewall . . . sometimes you have to look with a mirror, and you’ll see they’ve been leaking, and/or are still wet. They tend to leak onto #8 ignition coil. It’ll drip down the head and block, and you can see it from underneath

the heater hose coming off of the water pump

I believe your engine has a coolant crossover pipe, at the front. The seals often leak

The intake gasket can’t be the cause of the leak, because there’s no coolant going through the intake on this engine

As for the misfire, it could be something as simple as you need an ignition tuneup, or it could be something as serious as the engine wiring harness is brittle, causing the problem.

I don’t know how serious the misfire is, but if you want some peace of mind, you could perform a compression test. If #5 compression is extremely low, versus the others, then it obviously won’t be cheap and easy fix.

A word to the wise . . . if you do decide to perform an ignition tuneup, replace the plugs, wires, AND the heat shields that go around the end of the wires. There is an extremely good chance you will damage the wires and heat shields during removal, even if you are being very careful.

If the misfire is constant and severe, you can swap coils and see if the misfire moves. Obviously, this diagnostic strategy only works if you have a scanner. If the miss follows the coil, it’s bad. If it stays on #5, more testing is in order.

Heads are not tough for the iron duke!

should have heeded warning lamp und MIL

To try and give you more detail, it’s time and is well due for a top end rebuild ( I need tires - perelli )
Two days and its not hard for me to find 3 gasket sets, plugs and file/polish heads - some valve seat damage is typical and not necessary at this mileage. Um perhaps a water pump?

Please forgive me . . .

But you are making absolutely no sense

The “iron duke” was a GM inline 4 cylinder engine. It was never offered in a 1/2-ton truck

I think your screen name is apt. You blurt out comments so fast . . . before you’ve had the time to think about if they even make sense. Which they don’t, in this situation

And you talking about needing Pirelli tires . . . what on earth does that have to do with a top end rebuild . . . or ANYTHING, for that matter

I suppose your screen name alludes to the Paul Newman character from the movie “The Hustler” . . . ?


Update. Well the problem let me know itself. The water blew up on me. Was replaced all is quiet

Glad to hear it

How’s it going with that misfire?


Had it plugged into a code reader when the light tripped. Cylinder 5 is the culprit. Next on the list is plugs and wires see if that resolves anything. Motor doesn’t have the GM tick so that’s good. Have not done a compression test. Hopes it’s not a bad lifter

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Water pump. Excuse my poor grammar