I was looking down on the motor from the bedroom access panel today and I noticed coolant at the rear of the motor on top of the trans housing. I wiped it up and turned on the motor and observed for a bit. I then saw coolant oozing out where the head and the block meet. I am not a mechanic but I suppose this is where the head gasket is located. I just did an oil analysis from Blackstone last week and there was no coolant in the oil. I have been loosing coolant for awhile, replacing a gallon about every 500 miles. Now we are getting ready to take a 600 mile trip in a couple days. How serious is my problem and should I cancel the trip?

Take the coach to a reputable shop and start by having the coolant system pressure checked. If it has less than 16# of pressure you have a leak. If you drive with a leaking head gasket the leak area will get very hot and crack the head or the block or both. The damage that now might cost a few hundred dollars to fix can easily become thousands for a new engine.

Thanks Tom. I was wondering if poring in a gasket sealant would work.

Some sealants work OK for radiator leaks, but the conditions at the head are much more severe - and critical. You don't want coolant in the oil nor in the cylinders.

The only trip you should take is to the shop.

Consider going to a heavy industrial Cummins trained shop and tell them you want to pay for diagnosis and you will get several estimates before authorizing repairs. A motorhome owner with a suspected head gasket failure invites a big bill, you should have at least two shops give their opinions. Best wishes and good luck.

A gallon per 500 miles is a serious leak. Agree with Tom, take it to a good shop (2nd opinion is always needed) for their findings.

NEVER use gasket sealant! It will gum up the oil cooler in the block and cause further damage to the cooling system.

On the brighter side, I believe there is a coolant connection at the rear of the block that goes to the front dash heater. Maybe? But if you are seeing the coolant "oozing" at the head block junction, it probably is the head gasket.

I had a head gasket leak at the thermostat area (5.9L) and indeed it was the head gasket. It cost me $600 in just the parts. This could be a couple of thousand $ repair for parts and labor.

quote:

The only trip you should take is to the shop.

Fred, the above reply from Rusty echoes the thoughts of everyone here. Thank God you noticed the leak before leaving on your trip. You could be at the mercy of a mechanic you need on the highway. Not to mention a tow and other related problems that could occur if you take the trip without the proper repairs.

---

Lucky to find it before a real disaster.

The only thing I can suggest is to retorque the head bolts. You might be able to stop the leak if they are loose. Still requires removal of valve covers but can be done semi skilled amateurs like us.

I took it to the shop today and had a pressure test. The reading was eight. They also showed me where it was leaking which is what I suspected. They are putting on a new head gasket and also they are putting on a new muffler and some new exhaust pipe because I was getting fumes inside the coach. They pointed out the exhaust leaks to me. They are also changing the oil. They are putting archer oil in it, has anybody heard of archer oil? Any way, it all comes to about $1800. They guarantee their work and I thought that was a great price. Looks like we will go on our trip to Alabama on Saturday or Sunday. Thanks to everyone for your input.

Steve......

semi-skilled amateurs like us??

You better speak for yourself.....I'll have you to know I could do that job in 15 minutes or less.....only if I could just find my crescent wrench...I know I laid it out in the yard somewhere...or maybe the flowerbed......

Price is very good considering what they are doing. Make sure they check for any broken exhaust manifold bolts, cracked manifold while the head is off.

CHeck to see if the head will have to be retorqued after so many miles. Not common, but some gaskets still require it.

quote:

I'll have you to know I could do that job in 15 minutes or less.....only if I could just find my crescent wrench...I know I laid it out in the yard somewhere...or maybe the flowerbed......

Always use the right tool - in this case pliers....

Head bolts are "torque-to-yeild" bolts and do not need to be re-torqued. Once they are torqued with proper initial torque and then angle set they should not be changed. I never like that system but it does work and saves a lot of work later.

The valve lash should be checked after 10K miles.

Umm, the head has to be removed to change the gasket and they will replace the head bolts, but you can have them install ARP studs in lieu of the bolts. Studs are stronger and provide fool proof torque to the head. A full set on a diesel will cost about $400 (less if you deduct the cost of the new bolts) and will never require any maintenance. I suspect your leak resulted from a loosening or stretching of the original bolts. Studs will prevent that from ever re-occuring.

Always use the right tool....

In engineering school, I did a work study program with a group of machinists at Firestone Tire Company....

They taught me....

Measure with a micrometer.....
Mark with chalk....
Cut with an axe.....