Community Forums

Tonykeys · 10-27-2015, 04:59 PM

We purchased our MH a few months ago.
We traveled 500 miles to bring her home.

I noticed no fan shroud and ocasionally the fan would roar and temps would fluctuate 197-238 depending on stopped, city or road.

I just ordered a new WH fan, shroud kit and many other items.

Now,
When we purchased the RV I did notice a slight white smoke minimal out of 1 muffler tip, passenger side. The smoke goes away when warmed up so I put it aside thinking it was ok.

Recently I noticed that on my 500 mile trip it didnt use antifreeze but when I drove it to the muffler shop it seemed to use anitfeeze as my level drop in the container.
So I think it has a small head gasket leak on that side.
Im hoping its just the head gasket.

So how much labor is removing heads?
How much does it cost?
Assuming I get all GM, WHAT VEHICLE CAN I USE FOR ORDERING PARTS?

Should I get the heads decked or check for cracks and straighteness.

I figure I should resolve this now rather than hurt the motor on the road.

I get so many different water pump # GM and dont know the right one.

Im changing all valve cover gaskets, head gaskets, exhaust manifold gaskets, intake gaskets, spark plugs etc.
Any thing else Im missing so I can have all parts.

If I use a 2002 AVALANCHE 2500 8.1 for search on gmdirect is that OK?

Thks!

cb1000rider · 10-27-2015, 06:52 PM

I'd start with verification of an HG leak. The way I detect those leaks is by using a leak-down test on the cylinder and looking for pressure in the cooling system, but it doesn't have to manifest that way. There are test kits for antifreeze in the exhaust, visual inspection of pistons (HG leaks really clean), etc.

Decking and magnfluxing the heads is a good idea, but again, your mechanic may only want to work with a specific machine shop. And sometimes machine shops have pretty long wait periods...

Shop labor is typically done by "book" rates. These are rates of how long the job should take. They have nothing to do with how long the job actually takes - and typically you'll pay the book rate and the mechanic can do it faster. This is true of your local GM dealer and true of many other shops.
Labor rates differ. It may be hard to find book rates on an RV, they'll certainly have them for a truck with a similar motor.

With a 34' bounder, I suspect you'll run into the "RV" issue - that is, although it's based on a truck, most shops aren't setup to put a 34' vehicle into a bay. It may actually be easier to do a HG job on a class-A if access is good.

Start with the verification of a HG issue before you get too far down the rabbit hole.

Tonykeys · 10-27-2015, 07:58 PM

I guess I will get some help to verify 100% before ordering 600$ worth of parts and $1,000 in labor +/-.

But to order parts

What year and make truck can I use when ordering engine parts for the 8.1?
Is the 2002 ( MH year ) Silverado or Avalanche 2500/3500 a good source?

THks!

srh · 10-27-2015, 08:10 PM

I just lost almost 10 gallons of coolant on my Cummins 600 ISX. It turned out I had a leaking circulating pump. You may want to look at the inexpensive and easy to check issues before you order a HG.
Good luck with your find!

Davel · 10-28-2015, 12:19 AM

The only way to accurately check coolant levels is to remove the radiator cap. The overflow tank can lead you astray. There is a WH bulletin on this at the top of the WH forum page.
It takes a lot to hurt the 8.1, which I recently found out when I had a sudden coolant loss. The gauges all pegged out but in the end the motor is fine. After you replace the fan shroud and make sure all the rubber shrouds are in place around the radiator give it another test drive. You may have to find another WH chassis coach to make sure everything is in order. If any of the rubber shrouding is not in place the coolant system will not work right.

Good luck,
Dave

Arch Hoagland · 10-28-2015, 12:23 AM

The 8.1 in a motorhome is different than an 8.1 in an Avalanche.

I know this because I had a 2003 GMC 2500 with an 8.1. It had piston slap so bad it sounded like a diesel.

My Workhorse 8.1 has no piston slap and I mentioned that to the shop foreman at the Workhorse service shop and he said it's because some of the engine parts are different in the 8.1 engines for RV's. They are built stronger.

So I'd be careful what you order and also from who.

Tonykeys · 11-25-2015, 10:54 PM

Just an update regarding head leaks...

I recently did a coolant flush and new thermostate along with many other items as preventive maintenance...serpentine, tensioner, idler pulley, fan shroud, greased all fittings under Etc.

What I did notice is, these RV drip condensation from exhaust since they sit and there exhaust system is huge. I thought the dripping was water from engine. Wow. It can really scare someone when cold and especially in south FL.

Lash · 11-30-2015, 11:22 AM

In diagnosing a problem with the Wabco brake system, the shop noticed a slight leak between the head and block on my UFO. They pulled the bank of plugs on that side and cranked engine and noticed a fine mist spray into one of the cylinders on that side.

Made the decision to change both head gaskets as well as plugs, wires, and lot of other things since they were in there. If I back out the cost of resolving my Wabco problem, the cost of parts and labor to do the work was $8500 and took one week to accomplish. As the UFO is rear engine, all the work was done by tech lying on his stomach and on his head. Not fun for sure. Labor portion was for around 55 hours work and was on the order of $5500.

The heads were decked in Albuquerque and came up clean. New valve guide seals were installed.

Work was done at Hal Burns Trucking in Santa Fe, NM as this is one of the only places I trust to have a quality job done.

Expensive for sure but better than new engine.

I found that I would have to add about two cups of antifreeze weekly on a 2400 mile trip.

Not sure this adds anything to your thread but gives you some idea of costs and troubleshooting.

Regards

dieselclacker · 11-30-2015, 08:17 PM

Was the head gasget problem maybe caused by overheating due to the waterpump problem some of the early UFO chassis had? Did you have a waterpump failure early on in your motorhome. I recall reading about someone else having a problem with head gasgets in UFO coach, can't remember where. Glad you got it fixed before it got worse.

Timay · 11-30-2015, 08:39 PM

Quote:

Originally Posted by Lash

I found that I would have to add about two cups of antifreeze weekly on a 2400 mile trip.

Regards

Sounds like you still have an antifreeze leak. Take it back to the shop and have it checked. You should never have to add antifreeze as a weekly item.

Tim

UFO Pilot · 11-30-2015, 08:47 PM

Quote:

Originally Posted by Timay

Sounds like you still have an antifreeze leak. Take it back to the shop and have it checked. You should never have to add antifreeze as a weekly item.

Tim

I believe he was adding anti freeze prior to having the gaskets replaced.

Lash · 12-01-2015, 08:35 AM

Have never had a water pump failure or other issue in regards to head gasket leak. I have never noticed any liquids on the garage floor until last October and then it appeared to be condensation from the "dry" Houston weather.

UFO Pilot is correct in that the antifreeze addition was prior to repairing the head gasket leaks.

Regards

dieselclacker · 12-01-2015, 02:37 PM

Lash,

Thanks for the info. I was just curious as to what caused the failure, I thought maybe you had a waterpump problem which caused an overheat condition, leading to a gasget failure. Expensive for sure, but could have been a lot worse had you not detected and repaired the problem early.

Tonykeys · 12-01-2015, 08:04 PM

THe head gasket or heads were not damaged.

I was too quick to assume that maybe since the exhaust dripped or smoked like hunidity when cold startup that I had a blown head gasket or head damage. The 8.1 exhaust is big so when the humidity set in for a week or more, it would drip like crazy at cold start ups.

My fan clutch was bad and I ran it without a fan shroud since the previous owner sold it to me like that. I didnt notice that and always saw fluctuation in my temps.

I replaced everything that needed replacing and did a complete engine and chasis service.

Im happy to report that we did a 800 mile trip this Thanksgiving weekend for 5 days and it ran like a champ. Everything runs as it should thankfully!!!

Leaving again Thursday to put some more time on her!