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TXwannabe · 08-09-2015, 08:09 PM

Just completed our first significant summer trip since purchasing our new to us Phaeton last Fall. Left San Antonio and headed to visit family in Colorado (near Boulder), towing our CR-V toad. Seeing as Texas temps are currently in the 100 degree area, experienced our first overheating issue anytime we were in the Hill Country of Texas or even in a slight up grade if it was fairly long.
Although Honda allows towing up to 65 mph, we typically set the cruise to 60-63 on the open road.
Temp gauge normally sits halfway between 1/4 & 1/2 marks. As I noticed the gauge at the halfway point and above, we slowed down, dropped the Allison to 5th to speed up the engine speed somewhat, even dropped down to 4th to get the RPMs over 2000, but still had to pull over to cool down multiple times on the drive yesterday. Made for a lengthy and somewhat testy day.

Had a similar but much less severe problem on the outbound trip, tried to verify radiator was full (in the morning) but design/location of the rad on this model made that check a challenge of its own! However, I was able to get the rad cap removed and was able to get a couple of fingers into the neck of the rad to verify I at least got my fingers wet! Looking at the Cat owners manual, I see that coolant life seems to be 150k mile minimum (current mileage 46k), but nothing mentioned about age of coolant, and coach is at the 10 year mark now. Also, was running the genset to keep a roof AC running in this heat, so tried turning off the gen, since i assumed the cooling of the genset is through my engine rad? Is that a correct assumption? Also, made sure dash air was off, as also assumed the same issue could exist with engine rad providing cooling for the a/c.

This being our first DP, I'm not sure where to proceed next? Do DP's have thermostats like a car does? If so, do they stick after a while? Possible that I need to flush the rad?
I'm sure there are other possible issues I'm not even aware of, so I turn to the expertise of IRV2 to steer me in the right direction!

theroc · 08-09-2015, 08:27 PM

Have you cleaned the CAC and radiator since you purchased it? That's one of several reasons for rear-radiator coaches to overheat.

Click here for threads on this subject here at the iRV2 forums

theroc · 08-09-2015, 08:35 PM

Oops, sorry. Disregard my previous post. Your Phaeton could have a side radiator. But if it does have a rear radiator, make sure to put that important maintenance function on your list of regular "things to do."

Peralko · 08-09-2015, 08:46 PM

Good advice on making sure the radiator and CAC are clean. We had an overheating issue years ago, and it turned out there were a lot of leaves and stuff in between the radiators. Yes, your Cat has a thermostat, and they can stick, but unlikely. Does the fan run properly?
Your generator has it's own radiator, cooling it has no impact on the engine radiator, so you can use for AC or whatever suits your fancy. The dash AC does run off the engine, so it is an added load on the engine--something you want to avoid in an over heating situation.
Good luck!

TXwannabe · 08-09-2015, 08:49 PM

Quote:

Originally Posted by theroc

Oops, sorry. Disregard my previous post. Your Phaeton could have a side radiator. But if it does have a rear radiator, make sure to put that important maintenance function on your list of regular "things to do."

Not sure about newer models, but in 2005 it's a rear rad!

theroc · 08-09-2015, 09:11 PM

Ah okay. So take a look through those threads in the link I posted previously. At least it will give you a good idea what's entailed to clean a rear radiator and CAC.

When you go to the link, the iRV2 directory states "Page Title: Error 400 (Bad Request)!!1" but click on the "Continue to External Link >" and you'll be able to see the list of threads pertaining to this subject.

gemert · 08-09-2015, 09:32 PM

No idea about yours but mine has a coolant filter, or did, had it removed and put CAT ELC in instead. The filter also supplied SCAs for the radiator to be efficient. I think the filter is supposed to be changed every couple of years.

FIRE UP · 08-09-2015, 10:00 PM

TX,
You have a PM.
Scott

IASM · 08-09-2015, 10:12 PM

One thing im wondering is what the temp actualy is. Going by marks on a simple dash gauge does not indicated out of range temp. The hot temps will test systems and weaknesses will come up. You should have an expansion tank so im not sure when you checked the coolant were you at the radiator or the tank. Your gen should be running on its own coolant and rad but you need to check that coolant level also. Make sure radiator and charge air cooler are clean. They are all stacked along with the ac condenser so a gentle spray of water both directions helps. Silver leaf pc version is helpful when watching these temps. You should monitor your trans temps also since they tend to run together

strongcity · 08-09-2015, 10:26 PM

I'm assuming you have a rear radiator. If so we have almost the same setup. We have an 05 Newmar C-7 with a rear radiator and have had the same problem. We bought the motorhome in Sept. of 2011 and had no problem until the summer of 2012. We live in western Ok. We went to South Fork, Co. and would have to pull over to keep from overheating, when I would pull over with the load off of the engine the temp would fall very fast. I made the trip and made it home and washed and washed one the radiator and CAC cooler using the suggested simple green. Made another trip in 100 plus temp and engine still would heat on any incline. Washed some more still did not help. Finally had Warren Cat in OKC pull radiator to be cleaned. Found radiator very dirty. It only had a small air passage about a 4 inch circle for air flow in center of radiator. There is thermostats used on this engine. I would suggest pulling radiator for cleaning, replace thermostats, replace fan belt which also run ac compressor and alternator, also replace water pump belt. Plus what usually causes this problem is the road draft tube which is usually venting in front of the radiator leaving an oily film on radiator which collects dust and dirt from the road. This tube should be moved to the rear of radiator. If anyone ever overfills the crankcase with oil it goes out the road draft tube onto the radiator. If you do this I would also suggest checking the fan bearing on the engine fan. It is easy to replace with radiator out. Also I would probably replace hoses unless they look new. On the part on running generator causing engine to over heat it shouldn't because generator has it's own radiator at the generator. I'm in Colorado now and since radiator cleaning can pull the steep passes with no problem towing a GMC SUV in hot weather.

JFXG · 08-09-2015, 11:46 PM

One more vote for cleaning your rad and CAC. I had the same problem a couple of years ago, and couldn't believe what came out of those two units. A spray bottle of simple green ain't going to cut it. Freightliner of Utah used a pressure washer and steam hose, and they had a thick brown slurry running across their floor. When those things get clogged with oily road grit, they are a mess.

Good Luck!

EDALLSAILS · 08-10-2015, 08:06 PM

This may sound Stupid, but, have you checked your radiator cap? Our 2005 Damon Tuscany over heated on way from Florida to Pigeon Forge, TN. Replaced cap after pressure test and NO more temp problem. safe travels. Ed