Carver Owners Forum

Marina tells us that we need the coolant replaced in our Volvo diesel 370 engines as currently the antifreeze protection is at -25 & -28...How many hours of labour should it take to replace coolant in both engines...Also, how many litres of coolant does each engine take..Thx..

I'm assuming you're talking about a D6. If so, I believe it's 16.5 Lts. I'm also assuming you're talking degrees Celsius. I suspect that what they're reading is Volvo's Ready Mix Coolant which is normal at -28 deg C. That's all you'll get with that product and is why I don't use it in our part of the country. I only use the concentrate and add 40% water to protect to -54 deg C. I wouldn't expect it to take more than 2 hours to do both engines, 3 hours tops. That includes draining, filling, running engines to temp, purge, top up, and clean up. Access of course is everything, so really depends on how easy it is to get at everything.

Same for me. Went with the concentrate and mixed a solution to -45c. Being I had no experience on how to, there was a slight learning curve. Concocted a 12v transfer pump due to the limited access on the port engine which really made the job so much quicker/cleaner and easier. I did not want to take a chance on fluid type so I did go with the Volvo stuff, hard to come by and cost a mint. I believe it cost me close to $200 just in antifreeze! With my setup I could do it in a couple hours easy. Moving the couch and lifting the panels with care so as not to get things dirty, setup and mixing is half the battle. Still is close to 5 gallons of antifreeze/engine one needs to pump into something, remove and pour back into the engines. Good news is no special priming is required, in my case a top off after bringing engines up to temp and cooling down was all that was needed.

That being said I suspect this is a $500 job at minimum if done by a marine mechanic.

While we're on the subject, those of us that have closed cooling systems be it engines or generators, it's a good idea to have a refractometer for checking the coolant's protection level. These are more accurate and reliable than the cheap coolant tester/hydrometer we're all familiar with. Some will test propylene and ethylene glycol as well as windshield washer fluid and battery fluid. They can be calibrated to ensure accuracy. Look for one that's ATC (automatic temperature compensated).

Keep in mind that you will not get an accurate reading when testing propylene glycol (pink stuff). This typically goes for all types of testers though. The protection level reading will not be what is stated on the product label. This is because the product label will indicate the burst temperature that the product will protect to. Propylene glycol though will start to crystallize much sooner than that and that's the temperature the refractometer will read. So winterizing antifreeze rated for -50C burst protection for example will only read about -10C in the refractometer. There's many different ones out there, this is just an example:

https://www.amazon.ca/Antifreeze-Refractometer-Measuring-Automobile-Condition/dp/B01CQVHTCW/ref=sr_1_1_sspa?ie=UTF8&qid=1540345536&sr=8-1-spons&keywords=coolant+refractometer&psc=1

Thanks for that. I am used to using one for testing the salt content in my salt water aquarium. Did not know they were available for coolant. Will order one. Thanks.

Here is a great deal with case, tools and temp compensated. I did order one but since it comes from far it will take quite some time. Have ordered many, many times from Aliexpress which has included buyer protection just like eBay. Highly recommend shopping there. Prices are in CDN and I have never paid any import duties or taxes on any orders I have placed. https://www.aliexpress.com/item/High-Qu ... st=ae803_4

I suggest you select the standard aliexpress shipping for an additional $2 as you will get it much quicker. Probably 2 weeks as opposed to 2 months sometimes. This item is preorder, never done one of those before. Seems like it is only available Nov 11th.

Check the calibration before you test anything. It's probably already set from factory but it's best to confirm. You do that with distilled water. The reading should be at the "Waterline" at the bottom of the scale. Adjust by turning the screw under the little black cap/button.

Another note about measuring winterizing antifreeze. Some guys collect and reuse their antifreeze. It's especially important to confirm the protection level if you do this. As mentioned above, the reading won't be accurate so you need to set yourself a benchmark by taking a measurement from a new jug of the same brand and type and use that number as a benchmark. If the reading drops below that mark for the used liquid or liquid that you've had lying around for a few years, don't use it.

At work, we only use a refractometer for testing coolant and the acid level in batteries. I used to have that toy that sucks out the antifrezze and the little dial guage would move up and down. Not very accurate at all. It is a great investment.