Mysterious Coolant Leak

[Dustin Coffey]

Hello,
My name is Dustin, I just created this account. Here is my mysterious coolant leak issue.
You can watch a video I made to help you kind folks assist me in figuring this issue out.

Here is the link to the video, It’s on youtube.

http://www.youtube.com/watch?v=g4nv0jZPuKI&feature=youtu.be

My truck is a 1994 GMC SIERRA with the 4.3 Vortec V6

Topic

[Bill]

Great video.. It kinda looks like the Intake manifold gasket is leaking. If you add some cooling system leak dye to the coolant and view it with a black light, I bet you will be able to see where the leak is. After adding the dye you will need to run the engine until warm. to mix the dye with the coolant. Pick a spot where it’s not too bright helps to make it easier.

[Dustin Coffey]

Thanks so much, I’m only 17 and so far my repertoire only goes as far as the work I’ve done which is. Oil Changes, Brakes *Disc Only*, Brake Booster, windshield, wiper motor and master cylinder. And now this water pump, which is the only thing that hasn’t gone perfect yet. However I love the input Thanks so much anymore opinions will be adored also 😛

[Dustin Coffey]

Does Someone know what changing that Gasket entails, I agree that it’s probably the timing cover gasket. I would just love a quick synopsis of what I need and what I need to get it on their right.

[Bill]

Actually, Coffey I misinformed you. I just noticed the make of your truck and a timing cover will not leak coolant on that truck. I corrected my mistake and the most likely place is the intake manifold or the water pump gasket(s) slipped out of place when installing the pump. It’s happened to me a couple of times before.

I suggest you pull the pump back off and check.

[Dustin Coffey]

Hmmmm, I’m not saying you’re wrong. I thought the intake manifold was up higher than the leak which is occurring at the oil pan and bottom part of the engine block level. Is it possible that the leak could be travelling down the length of the engine without showing prominent signs of it ? And as for the gasket idea, I will check that soon. Most likely in about 4 hours. I will update then.

[Bill]

Sorry Dustin…It’s late here. Sometimes those intake gaskets leak in the corners and run down and drip off the bottom. If you remove the alternator bracket you might be able to see it.
I really think it’s a water pump gasket leaking though. Get a pressure tester if you can and give it a real good inspection before you start anything.

[Dustin Coffey]

Thanks for your help, It mean a lot especially since it’s late. I feel your pain though it’s 2:00 here cannot sleep with this leak on my mind though.

[Bill]

Yeah…we are in the same time zone…LoL

Get some sleep…A fresh mind works better than a sleepy one.

[Andrea Orsini-Boyer]

When i helped with a rebuild of a 302, it took 3 trys to get the water pump and gasket on properly..
Also, how long did you wait before putting the water in after putting the gasket sealing crap on? im not sure how well that stuff works when it’s fresh..

As for any other possible leak, i dont know those engines, so i cant say im the best man to tell you what’s what if it’s not the water pump gasket.

[Dustin Coffey]

I put the gaskets on with gasket sealer *to the pump itself* and then bolted the pump on to the engine again. It is likely that I screwed it up, because it was very tricky getting it on there. I waited a bit though, I completely reassembled everything once I put on the pump and then filled up the radiator

[richiepearce]

If that coolant leak was not there before carrying out the repair, the first thing to do is check that the work you did is not the cause.

[college man]

+++++1 on the above. I don’t know what vehicle this is.
But on some the bolts go into the water jacket need pipe
sealant on the threads.Also check that the different size
fasteners are in the correct location.

[Dustin Coffey]

Will Update the Repair tomorrow, just got done. Went to the lake today for 5 hours swam two miles, came home and went to work. So I’ll make an update video after school. Thanks

[Dustin Coffey]

Well, the repair is complete. I took the water pump back off as suggested and the original gaskets were tore up. So I went out and bought some fel-pro’s which are really high quality. Put them on there and all was well. The moral of this story and the lesson that was learned is that low quality gaskets will fail if not babied. And that letting your gasket adhesive dry before putting on the part is a good idea thanks for all your help.

[college man]

Lesson learned. Thanks for the update and the fix. 🙂

[Author]

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