3 Common Reasons Why Your Webasto Thermo Top C is Failing
A Webasto Thermo Top C is a high-tech (and highly welcomed) engine warmer that fits into your fuel line and keeps your engine from freezing up – all without having to idle the engine itself. As with any technology, it’s amazing when it works, but there are a lot of components and sometimes they fail for what seems like no reason.
While doing all of the heavy truck repair we do here at WTM, we see a lot of these Webastos, and some of the reasons for failure are far more common than others. Here are the top three that we see again and again in the course of our work.
1. You only use the Webasto when it’s cold out.
During the summer months, it’s easy to forget about the entire Webasto system in the engine, and you may go 100+ days without using it. If you’re not already aware – this is a big issue! The Webasto Thermo Top C is designed to be run at least once every thirty days, so you should be in the habit of starting it up and letting it run far more frequently than that. In fact, the warranty can be voided if you go longer than a month without doing so – so it’s absolutely in your best interest to stay on top of this.
So why does this occur? If the Webasto sits for weeks at a time, the mesh screen begins to get a build-up of carbonates and other minerals. The chambers get filled with hard carbon, and that won’t be removed without taking the whole mechanism apart to clean it. If you try to claim a warranty replacement or repair, and the company sees that build-up, it’s a surefire indicator that the proper usage schedule hasn’t been followed and they won’t cover the cost. It definitely pays to know about this before it’s too late.
2. Insufficient fuel supply.
If the standpipe of the Webasto is improperly installed, or cut too short, you could easily run into problems with enough fuel being fed into the device. Your fuel gauge may say you have ¼ tank, but if the Webasto’s intake pipe isn’t long enough to reach that amount, you’re going to run dry, and the results will be less than ideal – this will cause your Thermo Top C to fail, and may even cause long-term damage to the device.
3. Coolant bypass.
A Webasto Thermo Top C is a complex piece of equipment, and sometimes even the smallest details can cause major headaches. In many cases, there are two small O-rings in the exhaust compartment that are prone to hardening, leaving gaps, and eventually allowing leakage. We’ve often seen that coolant escapes and makes its way into the exhaust area. The presence of other materials causes the coolant to solidify, creating a gummy residue that coats everything and eventually prevents the Webasto from performing the way it’s supposed to. A prime example of this phenomenon can be seen in our instructional video, where we take the whole device apart and identify the problem.
If you have a Webasto engine warmer – or if you’re thinking about getting one – it can be a game-changer in cold climates like the one we have here in Calgary, or all around Alberta. But being aware of what they require, how they run, and what is expected of you as an owner will make sure that you get as much out of the device as you can, over many years to come. And should you ever find yourself with a Webasto that doesn’t want to start anymore, we’re always ready to help you out at West Tech Mobile!
Thank you for that wonderful video. I greatly appreciate the attention to detail. I am looking to purchase a webasto theromotop-c but see a newer model called EVO. Can the newer EVO model also be disassembled like the thermotop-c for service? thx! -Eric Boston, MA
West Tech Mobile
9/23/2020 04:25:07 pm
Yes it's all good with the EVO. Just go to Webasto website and there you can identify any parts you're looking for.
12/15/2020 07:08:21 pm
Is there a video about test the components of the Airtop C?
10/22/2021 04:02:19 pm
Feel that my webasto is over fueling. Getting fouled
4/30/2022 12:08:31 pm
We have a Webasto forced air diesel heater on our boat. circa 2008. It has and is working flawlessly for 15 years. My problem is it has always not worked well as far as the wall thermostat is concerned. It seems the set points are way to far apart. ie. temp when it shuts off is very hot and then it gets very cold before coming back on. Can the thermostat be adjusted?
9/28/2022 09:55:35 am
Hi, great video thanks..
11/25/2022 04:39:33 pm
Thanks for thee post
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