check your radiators

Topic: check your radiators (Read 3285 times) previous topic - next topic

check your radiators

May 08, 2011, 10:04:12 am

well i think i found the reason why the head gasket was blown on the gv i just saved from the wrecking yard. i hope that everyone at least checks the back side of your rads to make sure this doesnt happen to you.

Re: check your radiators

Reply #1 – May 08, 2011, 10:46:45 am

Actually, I suspect that is the FRONT (front of coach) of the radiator. And if there is a CAC (charge air cooler) installed it will be in front of the radiator and the dirt will be on the front of it.

A very common and well known issue with rear radiator coaches of all brands. You are basically a "vacuum cleaner" driving down the road. The dirt on the road is stirred up by the passing of 6 tires and your 36' coach. That air passes over the hot (and sometimes oily) rear axle, transmission and engine before the large fan sucks it up and pushes it through the radiator (or CAC and then radiator). The CAC or radiator then acts as a "filter" removing much of the dirt.

You need to clean the front piece of the cooling system at least annually and often more than that.

Brett

Re: check your radiators

Reply #2 – May 08, 2011, 12:01:18 pm

i agree with you on that as i see this alot at the radiator shop i work in. and the biggest tip i can give to every one is change your coolant every 2 year and save your self a big headace and cost

Re: check your radiators

Reply #3 – May 08, 2011, 03:20:50 pm

I agree, changing coolant is important-- basically every 3 years on "low silicate for diesel coolant with SCA" and every 6 years for one of the OAT based extended life coolants. Most of the OAT based coolants need a "booster" added after 3 years, but no SCA testing/adding and 6 year life.

But, this is totally unrelated to cleaning the OUTSIDE of the CAC or radiator.

Brett

Re: check your radiators

Reply #4 – May 08, 2011, 09:14:08 pm

Brett -

Several years ago I did some researching on "Extended Life" and OAT Coolants, and all those I looked at said "6 years" IF you also put in an additive package at 3 years. I discovered this "IF" at the 5-year point so I changed out both the Cummins and the Kubota coolants.

Look out for the fine print!

Re: check your radiators

Reply #5 – May 08, 2011, 10:29:21 pm

Quote from: mike – May 08, 2011, 10:04:12 am

well i think i found the reason why the head gasket was blown on the gv i just saved from the wrecking yard. i hope that everyone at least checks the back side of your rads to make sure this doesnt happen to you.

That happened to the previous owner of my U225. New rad and in-frame rebuild resulted on the 5.9 Cummins, setting him back $12.6K.

Is there a "correct" way to keep the rad/aftercooler clear? I do see an oily film and some dirt, and it strikes me that blowing back through (ie from the back of the coach) would work best. Water by itself I don't think will do the job; perhaps some engine degreaser spray on the front to first soften/loosen the dirt? Any thoughts?

Steve

Re: check your radiators

Reply #6 – May 08, 2011, 10:41:26 pm

Your on the right track. I used to use two cans of Oreilly's Engine Degreaser from the inside under the bed each year. When the radiator was pulled both the CAC and the radiator were very clean. The hardest part to get to is behind the fan cowling. You have to be a contortionist to get back in there with the spay.

I also brought a garden hose in through the bedroom window and sprayed down the CAC from the inside twice a year with just water and blew high pressure air through the radiator from the outside occasionally. Everyone who has a rear radiator needs to stay on top of keeping it and the CAC (intercooler) clean.

Re: check your radiators

Reply #7 – May 09, 2011, 08:01:00 am

Thanks Kent.

It was actually behind the cowling that the original rad was plugged the worst. Thinking that perhaps the cowling should be pulled once a year for a real thorough cleaning in there. Am also thinking a pressure washer would probably be a bad idea, with a good chance of bending fins. Solvent, garden hose, and compressed air (or my backpack blower) should do it. Strikes me that you need to be doubly diligent if traversing a lot of dirt roads or dusty areas, especially if you're seeping oil anywhere.

Steve

Re: check your radiators

Reply #8 – May 09, 2011, 08:39:20 am

Steve, you are correct regarding the high pressure water. I was warned many times to use only a garden hose. Once you have it clean, its pretty easy to keep clean.

If there are any oil leaks get them fixed.

Re: check your radiators

Reply #9 – May 09, 2011, 08:45:07 am

There will be two different answers here depending on whether the coach (as most are) ts equipped with a CAC (Charge Air Cooler-- aka Intercooler, aka After-cooler. All the same thing).

If no CAC, that means your "cooling system" is just the radiator and therefore one "layer" thick. Clean from the back-- reverse direction of air flow. This should knock the crud off the front of the radiator unless very clogged up in which case you may have to clean from the front as well.

BUT for the vast majority of those with a rear radiator, you also have a CAC. This means the "cooling system" is TWO, repeat TWO layers thick. It can not properly be cleaned from the back only. Enough PSI to go through the radiator, air gap and CAC with enough power to knock crud off the front of the CAC would be enough PSI to bend fins on the radiator. Yes, clean from the back as well, but the vast majority of the cleaning will be from the FRONT. Note, the fan blades sling the dirt to the perimeter, so you want to verify that the perimeter is as clean as the center.

And many CAC's are aluminum, so be very careful not to use harsh cleaners that are not compatible with aluminum.

And, if your crankcase breather (aka slobber tube) has not been extended to behind the air intake for the cooling system, DO SO. That way you are not putting oily vapor on the cooling system which materially speed up the clogging process.

Brett

Re: check your radiators

Reply #10 – May 09, 2011, 09:11:10 am

i used simple green and the soft spray at the car wash. but i had mine out and on a trailor

Re: check your radiators

Reply #11 – August 30, 2011, 12:54:35 pm

I had flushed out the radiator and CAC a couple times recently with a garden hose. Today, I removed the rubber cover across the bottom and did a thorough cleaning, and discovered that I had missed a lot. I pulled probably a gallon jug, maybe two, worth of leaves, feathers, gravel and dirt. I flushed thoroughly with a spray of Simple Green and a garden hose. It took a good 1/2 hour of constant flushing until the water started to flow clear. I had no idea I has missed so much stuff - it was not visible from the front, back or underneath, until the guard was removed.

I have a streak of junk in my driveway that came out!

oldMattB

Re: check your radiators

Reply #12 – August 30, 2011, 09:18:52 pm

Do the side mounted radiators require this same cleaning approach and frequency?

Re: check your radiators

Reply #13 – August 30, 2011, 09:46:58 pm

Any radiator at the rear of a vehicle picks up a lot more dirt from tires and low mounting than one higher up in clean air in the nose. Oil/fluid deposits from engine components can speed up the process. Especially true if you spend any time on gravel or dirt roads. Driving in the rain can also bring a mixture of debris to the bottom portion. You may not realize it is partially clogged until you head up that grade in hot weather. Not that much trouble to check.

Re: check your radiators

Reply #14 – August 30, 2011, 10:02:14 pm

Guys,

He has a 1994 U240. It IS a side radiator.

Picture driving down a road in the rain. The side of the coach has some mud on the side. That huge fan has pulled tens of thousands of cubic feet of that dirt and water ladened air through the CAC and radiator. A lot of that moisture evaporates when it hits the hot metal. The dirt is left. Does a side radiator need as much cleaning as a rear radiator. Does it need an annual cleaning-- YES. And, yes a trip to Alaska calls for several cleanings.

Brett

Re: check your radiators

Reply #15 – August 31, 2011, 04:37:59 pm

Brett,
Do all U300 Series have the rear radiator or did the later models have the side type ? I only know the 89 U300 with the 6V-92 300 Hp, with the rear radiator.

I had the rear radiator on the MCI when I put the 12V-71 in it, as the origional cooling setup was borderline with a 8V-71 @ 280 HP, Removed all of the original setup, installed the 5' X 6' radiator across the rear, using a pusher 54" fan, that worked until I went crazy with the 800++ HP, had to add the windshield washer fluid spray syaten, that worked super good, did not need a lot of fluid, maybe 1 qt. on a 5 mile mtn. Oh what joy.
Wish I could have had the space for a side mounted radiator setup, that is much more effective than the rear setup.

Re: check your radiators

Reply #16 – August 31, 2011, 06:45:39 pm

We found the same large quantity of debris, leaves, twigs, etc. between our charger air cooler and radiator with oil cooler in between. It was shocking and I think most stuff was stuck near the bottom. Mirrors and lamps helped see what was in between coolers.

We removed outside grill and one long side of the bottom conveyer-belt material and used a hose with a short tapered nozzle that looks like miniature fire hose nozzle.
After several hours of moving hose top, sides, bottom and again and again more stuff kept coming out.

When we were done, I used spray yellow insulation to seal the many gaps around the conveyer belts to force all air to flow only through the outside grill. Black spray paint hides the yellow color of hardened foam. The biggest advantage of this sealing is improved cooling as warm air exiting the radiator is not re-cycled by being sucked into the gaps around the radiator.

We put a piece of hardware screen cloth behind the outside grill to keep larger debris out, like cut grass and leaves. I think that when we drive slowly along a driveway that just had is side grass cut, the radiator fans act like a vacuum cleaner sucking the loose stuff into the side radiator.

Re: check your radiators

Reply #17 – August 31, 2011, 11:32:03 pm

Mine looks very clean and no sign of any "garbage" but I think I will heed the posts and have a go at cleaning. I recently had the left rear fibreglass panel off to do the muffler removal and it was very simple to do and went back perfectly with no proof of ever being off so I may just take the rad side off as it may give me a better chance to clean properly. I like the idea of screen on the back of louvres that Barry mentions doing.
John

Re: check your radiators

Reply #18 – August 31, 2011, 11:35:00 pm

Quote from: John Haygarth – August 31, 2011, 11:32:03 pm

Mine looks very clean and no sign of any "garbage" but I think I will heed the posts and have a go at cleaning. I recently had the left rear fibreglass panel off to do the muffler removal and it was very simple to do and went back perfectly with no proof of ever being off so I may just take the rad side off as it may give me a better chance to clean properly. I like the idea of screen on the back of louvres that Barry mentions doing.
John

Do. Ours was flushed from the inside and outside twice in the last 1,000 miles, and none of the junk or dirt was visible. I was amazed how much stuff was in there, and how long it took to flush it out.

oldMattB

Re: check your radiators

Reply #19 – September 02, 2011, 05:37:21 pm

Well am I glad I decided to look at the Rad etc to clean it even though it looked good. I took off the louvred cover and washed it from front and rear using Simple Green as noted and to get into the fan area I used a long brake line type of wand that fits onto a spray gun unit I had for undersealing my vehicles with "wax oil". This did a great job then I noticed that the small cooler for Trans' I gather was touching the outside of CAC fins as the 2 top holding bolts had come loose. Well as you will see in the photos I have a nice cut in the aluminum gallery and I will have to clean it all up good as I may have another caused by the a screw above this. Now my question to all you brilliant people out there in cyberspace is it ok to just seal the hole with something like fibreglass or?? as there is no water going thru, or something else. I will await the info
John

Re: check your radiators

Reply #20 – September 02, 2011, 05:43:01 pm

John,

The CAC is an air to air intercooler, so no liquid. BUT, a leak will allow turbo boost to leak out! If you have a boost gauge, what does it read (as compared with spec). And, I would drive the coach by a radiator repair shop for their recommendation on the proper fix. The CAC works under 25+ PSI, so it needs to be air tight! Loss of boost means less HP and less MPG.

Brett

Re: check your radiators

Reply #21 – September 02, 2011, 05:56:39 pm

Thanks Brett, I just knew you would be onto it right away. I have a boost gauge as there is a Banks Stinger on the 350 Cummins, but not sure what I should be getting as far as pressure.
I think I will clean it up really good and use a 2 part epoxy that is extremely tough (3M) to repair it with.
What do you think. I have not got the bus insured at present but can if needed, and the other option is to remove the fibreglass panel on the end and take the CAC off completely.

Re: check your radiators

Reply #22 – September 02, 2011, 06:02:29 pm

John,

With the Banks system, check with them as far as correct max boost. You could also have someone rev the engine (in neutral) and put some soap bubbles on the area to see if there is a leak.

I would NOT use epoxy or other home-remedy without consulting a radiator shop-- they do this for a living. If it is leaking, a good photo could give the shop enough info to give you advice. Be sure to verify that it is aluminum vs steel (use a magnet).

Brett

Re: check your radiators

Reply #23 – September 02, 2011, 06:14:13 pm

I have decide to take that panel off and take the CAC right off and do as you suggest. I will check but I am sure it is Aluminum.
Thanks again Brett
John

Re: check your radiators

Reply #24 – September 02, 2011, 06:28:53 pm

On my 8.3 mechanical with Banks, max boost was about 28#. They can tell you what your ISC is regulated to.

Affiliate Notice