I'm slowly but surely bringing my volvo 740gl's maintenance records up to date. Next on the list: coolant flush and fill. I've looked at the coolant and it is a nice bright blue green color. Also the radiator is a relatively new Nissin. I guess I'de just feel better knowing exactly when the fluid was changed. So the problem is I've never done this and my Chilton has already confused me. It says the petcock(drain plug) is under the dust shield below the radiator. I don't see it. Am I just looking too hard? Also, is it as simple as it seems: do I just drain it, flush it with a hose, then refill? Can I use tap water? Any advice is as always sincerely appreciated.

 

Use distilled water (look in the supermarket in the Laundry or Bottled Water sections).

Distilled water will have none of the deposit-forming minerals that your tap water may have. It's cheap, too.

The easiest way to flush the cooling system IMO is to buy one of those flushing tees. They fit in near the thermostat on the heater feed line, so you will be flushing the heater core as well as the radiator. Do Volvo red block engines have a coolant drain on the block? If so make sure you drain that too.

That's all I can help you with as I haven't yet changed coolant on my Volvo (I know it's only a year old, see). But I KNOW how you feel, I flushed the tranny fluid on Friday "just because".

Have Fun, and don't let any animals drink the old coolant if you spill any.

 

Yes there is a drain located in the block.It is on the left side of the engine above the oil filter.It is best to use a hose on it when you drain it.If not then the coolant drains through the cat converter and will smell for a while drying it out.

Flush it out with the distilled water and then fill it up.
When you fill it up fill it all the way to the top as far as you can.Then drive it for 6 miles to purge the air out of the system.Then the coolant should be at the max point.

 

Thanks guys I'll give it a try.

 

Good advice, I'll add that during the initial drive after filling the cooling system, hold the engine in low gear and get the revs into the upper range a couple times.

This increases coolant velocity which will minimize the possibilty of leaving air pockets in the coolant passages. Be sure to check the coolant level again after about a week.