Good Afternoon guys, I’m pretty new to this forum but have learned a lot already I fixed my misfire thanks to RonD, and a couple other guys on here. But I’ve always had a coolant leak in my 2004 3.0 and it has fried my catalytic converter. I am looking for best advice on where to start with this Coolant leak, and replacing my catalytic converter. I have had to put coolant in the radiator about once a week to keep from overheating, and checked my oil today it is a light brown color. The truck is parked and I am not driving it until I can fix this. Thank you in advance.

 

Also due to the fact that I’ve had to put so much coolant in the radiator (about a gallon a week) for the last month. The oil goes all the way up the dip stick. Also light brown color. So probably blown head gasket. Any advice here would be great. I bought the truck with the intention of rebuilding if the time comes.

 

 

I am thinking you had a major head gasket failure for that much coolant to be used up. You didn't notice any external coolant leak onto the pavement? Did you notice white smoke out of the exhaust? Hope your lower engine isn't damaged from hydrolocking. Anyhow, start with a compression test to determine if you have an issue with the heads or head gasket. If you get good compression, then move on to a leakdown test to find out where the leak is. Compression test is easier and less expensive to do (the kit to do the job is $30 at Harbor Freight) than a leakdown test which requires a more expensive tool and a compressor. Details on how to do the compression test are here.I am thinking your repair job entails a new water pump and radiator as well. More than likely new head gaskets. Probably even new heads.But yeah, start with the compression test don't go throwing replacement parts at it yet.

 

thank you for your input, no I don’t notice any exterior coolant leak whatsoever. There is white smoke coming from the exhaust but it’s not a crazy amount. And it’s only until the engine warms up. I put k seal in my radiator today, ran until hot then shut off. Haven’t done anything else. Major head gasket leak is what I’m thinking. But I will do the compression tests on it & keep updated.

 

Quick question, when doing the compression test do I have to remove all spark plugs before testing compression? Or can I remove one, test compression, place spark plug back in and move onto next?

 

They all have to be removed. Do a wet test too. Search the forum for info on that. Make sure the battery is charged good so you get a good crank.

 

If you didn't have an external coolant leak, radiator sealant wasn't necessary. That stuff just clogs up passage ways. Does more damage than good. I am thinking it was a bad move and pretty much put you on a path for a mandatory new radiator and maybe even heater core; the latter of which is a pain to do.

White smoke is a tell tell sign of a blown head gasket. Do the compression test anyway to be sure. The tester is a minimal expense and is a worthy tool to keep on your shop. You can rent one at an auto parts store too if you'd like.

Did you ever change out the PCV when you picked up your truck?

 

Stop leak I thought was to help with a head gasket leak. And I have not replaced the PCV valve in this truck yet, I actually priced a couple weeks ago after searching for a misfire and cleaning my MAF that it had been unplugged causing a CEL to come on. I plugged it back into the top of the engine and it has been good since. Do these valves tend to go bad? Compression test will be done on Friday. Any other recommendations I can do until then?

 

PCV's get clogged with carbon preventing the blowby from ventilating out of your cylinders. From what I understand, the un-ventilated pressure is exerted inside the cylinders and works its way into attacking the weakest point in the cylinder over time. That weakest point in your cylinder is your head gasket eventually leading to premature failure. Make sure you get an OEM Motorcraft PCV as it is like $2 more and less than $10. Change it out regularly too since it is so inexpensive and a simple job. Since you are going to do top end work head work, I would recommend getting an oil catch can (OCC) too. This one is an exact clone of the popular Fumoto OCC. Suggest you do some research on it. It is easy to install, but you do have to come up with your own mounting solution.

Stop leak/head gasket sealants just prolongs the inevitable at the expense of additional untold damages to other components. Your are losing a gallon a week in coolant, I don't think stop leak would have helped. I've heard of it working on minor leaks, but a gallon a week? That is $10/week extra in coolant. Plus the accompanying problems with prolonging the real fix. Hence your catalytic converter died too. Use of it does pretty much mean your coolant components do get clogged. Do the math on what the $20 K Seal solution is really costing you:

Catalytic converter is ???
Radiator is $100
Heater Core is $70
Thermostat is $7
OEM water pump is $70
New heads are $400

While a new head gasket set + new head bolts is $100 + elbow grease + time. I am no mechanic, but as a forum member going through something similar, my additional recommendations are: read this. Watch these videos: and . Because I am pretty certain you are headed towards a head/head gasket repair.

 

Roger that,

truck is sitting will do a compression test and keep this thread updated. Fully expecting to replace/remanufacture the heads. Definitely going to have to do this job myself to save money. Will replace cooling system as well as the catalytic converters. As far as replacing the cats how do I know which one to replace?

 

Update:

checked compression today here are results

CYLINDER 1
80/155

CYLINDER 2
80/155

CYLINDER 3
80/155

CYLINDER 4
80/155

CYLINDER 5
80/150

CYLINDER 6
80/155

compression seems to be good. Can someone explain what exactly that rules out?