Where is it going? Why is it running away?

[4x4Dreamer]

Okay, I actually have two issues today.

1st. I'm losing coolant. I don't see it dripping anywhere, however, the area between my tranny and engine are wet...but no puddles under the truck. I don't know if the moisture underneat is condensation from the AC or what. I lose about 1/2 pint every 60 miles or so.

2nd. I just changed my fuel filters and did an oil change. I've put about 100 miles on since then and when I start the truck now, it surges...a lot. I would imagine that all the air is out of the system by now, the line from the lift pump was replaced about 5k miles ago and is in good shape, and my IP has less than 10K miles on it. Any ideas?

[john8662]

For the coolant leak, it's possible that you have one of the blocking plates that resides on the back of the heads is leaking, which would make the back of the engine wet. Another possibility is the threads on the glow plug controller could be the source of the leak on the 82-84 glow controllers.

For the surging, check and make sure that your filters are making a good tight connection to the filter base and that the bleed valve on the primary fuel filter on the firewall isn't cracked open, and is tighly secured.

Anytime you suspect air in the system, it's a good troubleshooting measure to take a piece of clear tubing that is 1/4" ID to replace the fuel return line coming out of the injection pump. You'll just install this temporarily. You will then want to start the engine and let it run while you're watching it, if you can see air bubbles passing while it's running (after it's purged the line of course, first couple of seconds of running) then you're sucking air into the system somewhere.

[85-m1028]

I had a similar condition and found out later that I had a leaky gasket on one of my cross overs

[bmiszuk]

I had been looking coolant slowly for the past few months. I was seeing antifreeze on the left side of the engine near the back but could not find the exact leak.

It turned out to be a split radiator tank. Antifreeze was getting blown towards the rear when I drove. I did not find the exact problem until the tank ruptured completely (in my driveway). Even then I could not see the exact leak because it was hidden behind the shroud. It wasn't until the radiator was out of the vehicle that it was obvious.

My point? Leaking fluids can get blown around a lot on vehicles. Be careful not to jump to conclusions when troubleshooting. It's best to pressurize the system using one of those pumps that mounts where the radiator cap goes but if you're like me you don't have one and just spend a lot of time guessing :D

[4x4Dreamer]

My radiator is not even 8 months old, it had better not be the problem. :mad: