I noticed a 5 inch diameter leak under my 98 ranger 4.0l 4x4 each time I drive to work and back. It is located below the oil pan. When I got under the truck I can see coolant on the oil filter as well as the oil pan. It is also splashed back on the transmission. When I looked under the hood I can't really find where the leak is coming from. If I place a light down the back of the engine near the firewall on the passengers side, I can see steam rising up. So the coolant is coming from the passenger side but I can't pin point where.

I read the posts and I thought it was the lower intake manifold gasket. I can't really see behind the engine well with a mirror so I have now removed the upper intake manifold (great directions Rockledge!). I re-torqued the manifold bolts. Three of the bolts near the center of the manifold had to be tighened a bit. I am still not convinced that was the problem. I got behind the engine with a mirror and still can't see where it is coming from. No trace of coolant. The head is wet but I think (and hope!) it is from the valve cover. I need to change those gaskets too.

Sorry for the long explanation. Now to some quick questions;

1. Anyone have a similar problem?
2. If the leak is the lower manifold, how could I verify? Would the leak be observable?
3. If it's the head, has anyone has good results with Bar's stop leak? I am in Ottawa Canada so I would prefer to work on the head when it is warmer. (Tonight it is going to -20C, -4F)

Thanks in advance

 

It might be the heater core. I know that when my heater core began going out, It was ever so slightly leaking out of the pipe nipple that was at the bottom of the plenum that's inside the engine bay. Next thing I know, I have no coolant whatsoever, as I'm traveling on I-55 at 3am at 85mph. Not alot of fun to push/limp your truck 15 miles and get home at 9 in the morning. One way to check this theory is to run the heat and if it smells like anti-freeze, then it could very well be your heater core. Btw, it's a real PITA to change out if you haven't done it before.

 

That's a fairly large external leak which IMO makes it less likely to be an intake or head gasket issue. I agree with nate, sounds more like a heater core or heater hose problem. Maybe even a leaky "hot water valve" which is located in-line on one of the heater hoses (has a vacuum line coming off it).

 

As I read over your symptoms again, I'm thinking heater issues. Sounds like exactly what I went through.

For a quick fix on the heater core, you can route the core out of your cooling system, but then you'd be left with no heat in your 20 below weather. Yikes! It won't be fun to do in the cold. I can now do it in an hour if I have a buddy, but by myself will easily put me in upwards of 2 hours. I know this bc NAPA gave me a defective core so I had to take my dash out three times. Once for what I thought was the initial fix, a second time to try and fix my new core, and the third time for when they finally gave me a good core. Too bad I'm not in Ontario, bc I will work for food, lol.

Let us know if that ends up being your problem and if not, enlighten us so we can all have a better idea in the back of our minds to think ab when it happens to one of us.



One last note, check your passenger side floorboard for moisture. That's a tell-tale sign of heater core issues. Pull up the mat, that'd be the most likely place to find moisture.

Oh, I almost forgot, good luck!

 

Thanks for the info natebaker and Rockledge. I will take another look at the heater core.

A couple of more things WRT heater core issue.
I do not smell coolant in the cab. When I get out of the truck I do smell coolant. I believe it is evapourating off the exhaust manifold. I can see what I believe is the drain line from the heater core (lower passenger side of firewall), and it looks dry. I will check the passenger side floor. If it's wet (it's coolant so it shouldn't freeze) I thought I would smell it in the cab. It looks wet near the back of the passenger side head. I pulled the rear plug and it looks fine (typical carbon, not green). Perhaps it is the control valve spraying on the block. I inspected the value and I don't notice any evidence of a leak.

Question:
If I bundle up and drive the truck for 20 minutes without turning the heater on and have no leak, I guess that would suggest the heater core area. I am assuming no coolant would flow if I don't actuate the value via a vacuum line. Would the assumption be correct?

 

Follow up.

Went into the garage and passenger floor is dry as a bone. Looked more cloely at the drain tube and it looks dusty so I am not sure if any thing drained from it. Looked at the heater valve, Looks ok. Maybe I need to reassemble and got for a cold drive.

BTW Rockledge, Agreed! That EGR tube is a pain!

 

To put the issue to a close. It was the heater control valve. It would drip directly onto the exhaust manifold and evapourate so no indication would be there other than some white deposits. When I drove, the drip would splash onto the block looking as though it was leaking from the engine. So $22 later, the leak is fixed.

Thnaks for the input.

 

Glad to hear you found the problem.

I've read about a leaky heater control valve (a/k/a "hot water valve" a/k/a "water diverter valve") before, so it's I guess it's not really that uncommon.

For those people who don't know what one looks like, here is a pic:

http://homepage.mac.com/valerief/.Pictures/P9290018.JPG

 

Awesome! Glad to hear we got you straightened out! I'm also glad to hear that it was just the heater control valve. That's alot easier than a $60 heater core and backbreaking hours of work, lol.