DieselAllTheWay

OK to use Dex-Cool on a 450?

11 posts in this topic

Figured I started a new thread seeing how this isn't a starting related issue.

05 CDI 450 Cabrio was low on coolant and it blows cool air only, no matter what fan position or temp I set the controls to. Checked the coolant which is green (thankfully with no signs of oil in it). The recommended Merc stuff is blue. This indicates that the PO used cheap coolant at some point, likely after he replaced the starter. Naturally I'd like to replace that ASAP. But since I don't know if I'll ever be able to get this car to run and I have an unopened gallon of the Dex-Cool stuff from my now gone Jimmy, I wonder if I could use it in the meantime? Heard that Dex can gel up when mixed with other coolants. Plan to do a full flush but as we all know, it's nearly impossible to get all of the old stuff completely out. The label says it's safe for aluminum rads and is silicate and phosphate free. 

 

Am I safe to use this on the Smart? I know that the Merc stuff lasts 15 years (and Dex says 5y or 240,000km) so the math may not work to its benefit but atm I just hope to get some heat in the car till it is fully running. OK to use this in the meantime or is this stuff destructive to German engineering?

dex-cool.jpg

Edited by DieselAllTheWay

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how many blobs can you get to on your temp guage?  2 or 3.

no heat could be a stuck thermostat or mabey air trapped in the system.

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While driving around on the two diff days that I managed to get it started (including a bit of highway driving) it was showing around 80C, or 3 filled blobs. Despite this there was no heat at all. Outside temp around 4C. On the second day I had added a bit of distilled water to the reservoir in an attempt to raise the level. Made no diff as far as cabin heat went. Number of blobs remained at 3.

 

Below is a pic I took after day 1, mainly in order to check for possible oil mixed in. Took me a long time to figure out where to find the reservoir, longer to access it. Really could use an owners manual for this car, if someone has a spare or know where to find a PDF?

green-coolant-in-smart.jpg

Edited by DieselAllTheWay

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Block all but the top 5 inches of the rad off. My rad has only what you can see through the smiley face showing to allow air through . It stays this way until spring and is the only way to get good heat after about a 5-10 km drive. No warm up as it doesn't like to be left idling either......seems to trigger electrical issues. I simply drive it carefully until the heat starts climbing then as normal. I also use a oil pan stick on heat pad and give it a few hours before I plan of driving during the winter months. I also replaced my thermostat which made a world of difference......
As for coolant, as long as it's good for alluminium blocks etc i would assume it should be ok, but don't quote me on it......been wrong before...lol.  Bleed air out of system at thermostat also.

 

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IF you have 3 blobs you should be getting heat!
Heater fan motor working?  Rat's nest plugging up heater rad...or air ways?

 

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I agree, I should be getting heat seeing how the engine is hitting about 80C. But none. Air blower and temp control all seem to be working. Figure I start from scratch but definitely feel like replacing the green stuff in there to be a good first step, not knowing what the PO used.

 

After reading up on the many nightmares of Dex-Cool I figure it's best to stay away.

 

Napa has Zerex G-05, which seems to be the right stuff ($22.79, concentrated). Can Tire has this Motormaster one ($22) that their site recommends for the Smart, purported to last for 6 years. https://www.canadiantire.ca/en/pdp/motomaster-extended-life-diesel-concentrated-anti-freeze-coolant-3-78-l-0293052p.html

 

For all I know the PO didn't do a proper job draining the system and as Sydney pointed out, there could be air pockets in the system. For peace of mind this seems like a worthwhile thing to do. Will avoid driving the car other than to park it in the back of the house (a whopping 700m drive believe it or not) till I get this done. Procedure doesn't seem straight forward, will require assistance from you knowledgeable folks (insert emoji for cheap pandering pitch here)

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On ‎11‎/‎20‎/‎2020 at 1:52 PM, DieselAllTheWay said:

...........  the engine is hitting about 80C.

 

80C is the cutoff point between 2 blobs and three.  79C will give you two blobs.    That said, you should be getting lots of heat   If not, I would suggest checking for air bubbles or a blocked heater core.

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I decided not to risk it, it's only $22 for a gallon of the concentrated Zerex G05 spec coolant that is designed for Merc, Smart other German cars. It apparently is safe to use on diesels and unless mistaken it contains some nitrite (don't quote me on that only reporting what I have read some literature). 

 

As for the no heat issue I just had a chat with Willys (as in an actual conversation where words are exchanged, a nearly dead technology nowadays) and he had a very good advice that I plan to confirm very shortly: that the cable that controls the temp slider may have come loose. It makes sense as there's zero tension in the slider. Something I should have realized before but then again this car is brand new to me. And the day I drove it home it was the middle of summer, so it never occurred to me to slide it to the right. FF 4m and during my hour long drive at 4C I was frantically searching for heat. It was even colder the next day.

 

Will update when I get the chance to check the cable. According to Willys this is a common issue and a very easy fix.

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I think we are making far more than needed out of anitfreeze imho, it's an alluminium engine so pick a brand that deals with that and a diesel....you're main issue is don't allow it to freeze and also dilute it correctly so it allows some heat to build up.

I shoot for better than -35 or so on the tester and seem to have no issues.  On an older engine I wouldn't be spending the house on antifreeze but on a freshly built engine I may spend it? As they say oil is cheap, machine work isn't!  Same sort of goes for antifreeze.....but we do not drive the top super car and have it's finiky engine specs...imho....lol.

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