I had the heater core replaced already. This time the Plastic Coolant is the culprit all along. I will get my mechanic friend to help me see if the fan is working...I will let you know how it went....

 

Man, you do NOT need the engine to run any cooler than what the t-stat will keep it at. Mines runs around 186 most of the time. I does get up to as much as 213 when it's turned off an on during short trips but that is not a problem.

If you purhcased a gallon of the antifreeze, and it's not already mixed 50/50, you shouldn't need anymore. If you purchased 2 gallons of it, pre mixed 50/50, you shouldn't need any more.

 

Thermostat repair and coolant flush on a Volvo 850 Part 1 - YouTube
have you guys seen this video???

 

Dear patoygolf, I didn't recommend the Pentofrost I just said that's what Volvo recommends. There is nothing wrong with it but personally I just go with a name brand as it's cheaper and I've never had a problem with any of them. If I had the money I'd have no reservation with using the Pentofrost.

Big thing with antifreeze is never mix Dexcool with anything. That is unless it says clearly in the label "mixes with everything". Dexcool is the stuff GM came out with and it's nothing but a hassle. It's the first thing I do to any vehicle I own. It goes down the drain and a regular extended life yellow or green goes in. It's just easier if they are all the same.

As for the cooling additive, there are a number of them out there. Redline's Water Wetter, DEI's Radiator Relief, CRC's Enginekool and others. Standard car with slight improvements you should be fine.
If you've upped the output they can and do allow for a little better heat dissipation. Your thermostat can only open fully. Once it's all the way open then it's a matter of how much air you can pass heat to. Normally if you have a high performance engine and you push it a lot you might need a second "pusher" fan pushing air toward the radiator in addition to the stock fan. You can also replace the stock fan with something that will pull more air (CFM) or a bigger radiator which in a lot of cases means custom.

 

Hello KissaFrog, I thought you were recommending the Pentofrost? It's ok it that's what Volvo call for. I already bought 3 and they cost about $12.89 a 1.5 liter. Since my 1994 Volvo 850 calls for a 7.4 quarts of coolants, I will use 2.5 bottles of Pentofrost and equivalent of Distilled water to make it 50/50. And for RSPI thanks for the advice, I will just go with what I had mentioned above.

Well I have to go to work on the car and I'll keep you posted.. I just loved this Volvo of mine... At least when you worked on it, it doesn't talked back like a spouse after you just buy them a gift instead of saying thank you, you will get criticized for buying the wrong item. Hehehhehehe. I hope that never happens to you????