I just bought this truck a couple of weeks ago. Slowly I've been working through any perceived issues I have w/ it.

I have been getting a really slight antifreeze smell outside of the vehicle but was never able to see any leak. Well I topped off the antifreeze yesterday. I drove it around for a few miles and brought it back home. Again when I got out I smelled a slight wiff of the antifreeze, but didn't see any leaks.

I went in the house and came out about an hour later and noticed a good size puddle under the front of the truck. I turned the truck on and still no leaks.

It seems as though it only will drop coolant after it gets up to temperature and sits for a bit.

I'm just hoping someone can point me in the right direction here. Is there anything obvious that would show these symptoms, or is it just a matter of eliminating possibilities?

Oh and I noticed the previous owner had been putting some sort of stop leak in. Possibly for a while. It seems to be coating everything in the reservoir and the radiator.

Thanks,

Josh

 

Classic symptoms of lower intake manifold gasket leaks on 1996 and newer 4.3L engines. The most common places to leak are at the front and rear corners of each gasket. A cooling system pressure test will confirm the leak. Felpro has a new design gasket set, MS98002T. If the gasket surfaces are properly cleaned, the new gaskets are installed correctly and torqued properly, it will not leak.

 

Crap!! I was really hoping it was the water pump. What's the average shop bill for this repair?

 

Flat rate labor time is 4.3 hours and about $100 in parts. A pressure test will tell what's leaking, it could be the water pump, who knows

 

Its also the signs of a waterpump but if its pouring out of that its easily seen. My money on intake.

 

So of course you guys were right. It was the LIM gasket. Thanks.

I changed it today w/ the recommended FelPro.

Once I got the LIM off, I was really surprised by the amount of gunk in the coolant passageways. Hell, the one on the left closest to the firewall was completely plugged. Unfortunately, a good portion of that plug of goop dropped back into the block when I went to scrape it out. I guess, I'll flush the whole system tomorrow. Any good tips on bypassing the heater core to do a flush without pushing the gunk through the core? I figure on just getting a ****** fitting, but I noticed the hoses are two different sizes.

 

Pull both hoses off the core, along with the upper and lower radiator hoses, and flush both directions in the heater hoses. Then flush the core both directions. Then flush both ways through the radiator. Connect all the hoses and fill her up 50/50 with Dexcool & burp it...... done.

 

OH,,,OK. That's a great idea. You've probably given that advise dozens of times.

I was just gonna take off the lower radiator hose and put a garden hose in the top of the radiator and turn the truck on and let it run. Your way sounds a lot safer. Thanks.

Just a garden hose for the radiator flush as well?

While I have your ear,,,,,, I noticed a lot of oil sludge in the top end while I was doing this repair today. I've never torn this much of the top end off before. Is it normal to have this thick sludge in a vehicle of this age at 110,000? I scraped wiped as much off the upper and lower as I could, but I gotta think there is still a ton of this crap in the heads and block.

 

Flushing each individual component separately is the safest and most effective way to flush a cooling system. It also avoids flushing crap from one area of the cooling system to another. You can tell right away when each component is clear.

Sludge in an engine, no matter what the mileage, comes from not changing the oil & filter often enough. If the thermostat doesn't allow the engine to reach 195F, it speeds up the process and the sludge gets worse. The use of kerosene or motor flush additives is not recommended as they can/will dislodge chunks of sludge. If/when that happens, the chunks will clog the oil pick up screen for the oil pump.... no oil flow or pressure = toasted engine, real quick. Once an engine is sludged up, take it completely apart and clean it, or cross your fingers and leave it alone until it dies on its own.

 

If you had an LIM leak, then the oil sludge is due to contamination with water. Always do an oil change after replacing the manifold gasket. For a gentle, thorough cleaning I would use Auto-Rx.