Thermo Replace

[bobsyouruncle]

Hello everybody- Trying to replace the thermostat on my 2000 V70 and in the instructions it says drain 2 liters but I thought maybe I will just flush it all but couldn't find instruction on how much coolant goes in so I was just going to do the 2 liters so I could replace the thermostat. Started draining and I thought the coolant color would be green, pink etc but it was brown(hope that's not bad). Maybe that's the color of volvo coolant? I would like to put new coolant in I have Prestone Extended Life which I read on here works or I have some G12 Audi/VW. Which is better? I don't have a volvo dealer within 3 hours of me to buy any. How much coolant goes in total if I change it all? Is there another place to drain it from besides where the instruction said? Please help, car is on the ramps! Thanks!!!!

[cn90]

1. Read this DIY, watch the tstat bolts: don't strip them!!!
https://www.matthewsvolvosite.com/forums ... =1&t=50745

2. If brown color and unknown service history, flush the system.

3. Drain from lower rad hose. Do not open the petcock on the radiator, it likely will break!

Best is to:
- Drain old coolant.
- Gently re-attach lower rad hose
- Add fresh water to system, run engine for a few minutes.
- Drain coolant
- Repeat another time to get rid of old coolant.

- Replace tstat
- Some water will remain in the system (not much but some will be in the system).

---> Capacity: 7.6 US qts (7.2 liters)
---> Turbo-charged models: 7.4 US qts (7.0 liters)

- Add pure coolant (not the premix type), whatever you do, the system will need approx. 3.8 qts of pure coolant to achieve a 50-50 mix.

[Ozark Lee]

It is standard operating procedure to replace the ECT sensor at the same time that you change the thermostat. The ECT sensor is pricey but it can cause a lot of grief when it goes bad.

I also highly recommend that the thermostat cover bolts be replaced with the updated coated steel bolts.

...Lee

[erikv11]

To answer your questions about coolant brand: A lot of people use Prestone or other green coolants on these cars. Even though those coolants are not the HOAT formulation that Volvo recommends, they seem to work OK. Unfortunately it is a long-term issue, i.e. it may take 10years before you really know.

The HOAT you can buy at most auto parts stores is Zerex G-05. That's what I use. It is a clear color.

It isn't obvious in cn90's post up there but what he means is flush until the system is flowing clear water only. No brown (or green or red or whatever). Then drain one more time, add 3.8 qts coolant, top off with water.

It actually can take several changes to flush out the cooling system until the water runs clear - two likely won;t do it, three might. It will help to drain the block too, there is a port for that on the side closest to the firewall, accessible from under the car.

And finally, it is a hassle but you should use distilled water not tap water.

[cn90]

FWIW, what Volvo recommends is what Volvo recommends.
Sometimes I pay attention to what they say, and sometimes no.
Volvo says AT fluid should last the life of the car, go figure.

The Zerex issue has been beaten to death in BMW forums.

I am not saying Volvo is right or wrong, all I say is: you can use Zerex or Prestone and you will be fine.

Just google "antifreeze hoat vs prestone" and you can read more then you ever care for.

I have used strictly Prestone in my BMWs, Hondas and multiple Volvos (1991 240, V70, S70) for 25 years, zero problems.

Coolant is almost like engine oil, it is not so much brand name but the change interval that matters. I replace my coolant every 3-4 years or so.

[erikv11]

I think that advice will not get anyone into trouble, I see your point.

Keep in mind that most Prestone is OAT which is not compatible with HOAT - you shouldn't mix them.

One of my big complaints with the non-HOAT coolants is the claims like "works for every car!!" and "Magic!" on the front of the bottle. If you buy Zerex G-05 you know exactly what you are getting, and you know the chemistry is OK with the aluminum engine.

[cn90]

The long answer is by Larry Carley:
http://www.counterman.com/article/86425 ... years.aspx

The short answer is:

"Regardless of what type of coolant a customer chooses to use in their vehicle, there are a couple of key points to keep in mind: Different brands and types of coolants can be mixed together. It won’t cause an engine to overheat, or the cooling system to sludge up, or allow corrosion to destroy the engine, radiator or gaskets. But, adding traditional green antifreeze to a cooling system that already contains a long life OAT or HOAT antifreeze will shorten the service life of the coolant to that of a regular coolant (24 months or 30,000 miles).".

[erikv11]

Right: you shouldn't mix them. Even shorter.

And Larry's is *one* answer, not *the* answer.