Rialta Temperature Alarm Comes On

[Hobart]

2003 Rialta motorhome on Volkswagon chassis. Temperature light and alarm come on while coasting downhill. Gauge stays constant at 190degrees. Light goes off after 10 seconds and comes on again a minute or two later or when we begin another long downhill. Any suggestions would be appreciated.

[Roadtrek Adventuous RS1]

Originally Posted by Hobart

2003 Rialta motorhome on Volkswagon chassis. Temperature light and alarm come on while coasting downhill. Gauge stays constant at 190degrees. Light goes off after 10 seconds and comes on again a minute or two later or when we begin another long downhill. Any suggestions would be appreciated.

Hmm, light came on for 10 seconds and comes back again...... either it's a malfunctioning light or you have a problem.... 190 sounds normal... cool that you have a guage and a light.

BUT, overheating is one of the most dangerous things.....

I would have it all checked out professionally.... when did you last have a complete service on the radiator, coolant change, thermostat and water pump checked ...

Did you notice any loss of power at any time going uphill???

You're going to sleep easier once you know what's going on??? I wouldn't delay on getting a qualified answer......

Happy Thanksgiving.....

[kite_rider]

I didn't have that issue, but had other weird cooling issues with Eurovans I've owned over the years. Check the big green radiator resistors, they fail frequently.. When they go bad only one (or none!) of your two fans works and that leads to some odd cooling symptoms. Also the fan fuses have gone bad on me as well.

Best to find this issue ASAP since overheating that expensive engine would be really bad.

[booster]

Not in VW's as I haven't had them, but I have seen similar in other vehicles that had failing thermostats or water pump issues.



What appears to happen is that the thermostat will be open quite a ways on the level or wide open if you just finished a climb. You go over the hill and the engine goes to idle, plus whatever the backwards torque converter will do for rpm lifting, so the water flow is much reduced. Since the engine is still hot inside it gets cooled less from less water until a bit of time goes by and temp drops. It probably has always done it somewhat, but maybe the pump is getting weak or the warning temp sensor has drifted enough to cause the warning.


When you go over a hill and know that the light is going to come on, try revving the engine to a bit a short of accelerating. It is very possible that will keep the light off, and then you would at least know where to look to fix it.

[Hobart]

Update. I am leaning strongly towards a sensor malfunction. This morning the temperature alarm went off 10 seconds after I started the engine in 39 degree temperatures. I will see what is needed to replace it. Thanks to all of you for your help and advice.

[Eraygunz]

Hi.
My RT had a similar issue.
Always showed it was running a little cool....no matter what.
I live in Florida and found that strange? Come to find out the sensor was bad and that was all.
Now she reads the proper temp.
Good luck.
Eddie

[Brad1998RD]

Sensor or coolant level is not up to where it should be and you are hearing the low coolant alarm not overheating alarm

[HOBO]

Some Rialta specific information for you.

Baldy - A cornacopia of Rialta information.
Winnebago Rialta Motor Home

Rialta Tech forum
https://groups.io/g/Rialta-Tech

Rialta Owners Group of America Facebook page
www.facebook.com/groups/869040643201627

Enjoy
HOBO

[Bertiboo]

As a former 2002 Rialta owner (same 200hp VR6 as yours). I strongly recommend asking on the Rialta Tech forum mentioned above Do you have an external add on transmission oil cooler? If not the original cooler uses engine coolant to cool the transmission oil too. After a climb if the transmission get hot. It will keep transferring heat to the engine coolant for awhile after. But I think you would see a climb on the gauge if really hot so could be a sensor issue. I always had a Scangauge II connected to monitor both these temps while driving. Also highly recommended for Rialtas, to save your transmission.