Collant flushing and air lock in 1996 RT10

[mad prof]

I flushed the system couple of months ago but I have irrational temperatures, indicating there is an airlock. Replaced Tstat and pump is operating fine. No leaks and collant came out as I put it in. I must have done something wrong.*So I started again:I took off the fascia to have full access to all coolant reservoirs. I flushed the coolant by disconnecting the bottom hose of the radiator. I cleaned the front coolant recovery bottle. The pressure cap in the expansion tank looks fine, but I cannot test if it is self bleeding as the ones in Gen2 cars.

Can someone please take me through the steps to:
A) fill correctly the system and
B) purge any air*I really appreciate any help as I am taking the car to a long trip

[Matt M, Pa]

To a cool engine....remove the cap from the tank on the inner fender. Squeeze the upper hose on the drivers side as much as possible...use both hands. Air will bubble at the tank...then the level will drop. Add coolant...repeat..until bubbles do not appear when hose is compressed. (level will rise....but you don't want bubbles.)

[RoyV101621]

Perfect timing on your thread. (I'm trying to figure out where to place the tee for a garden hose flush.) Your coolant system needs to be burped. Remove the cap in the expansion tank. Bring the engine up to temperature. While the engine is running, Squeeze the top radiator hose. If there is air in the system, you will feel the air rush and see turbulence at tbe openning of the expansion tank. Continue to add coolant and squeeze the top hose until all the air has escaped.

[Luisv]

The Viper is a self purging system. There is nothhing special to do other than to drive the car for about an hour with a radiator and pressure bottle full.

If you completely drained the system then fill it via the pressure bottle (outside the fascia) slowly. The radiator will fill as well. If you need to (fill takes too long) then you can remove the bleed screw on the thermostat housing. It is visible under the front-most intake manifold runner. It is a square drive if memory serves. Then continue to fill until you get some coolant come up and out. That should do it. If you want, turn the heater on in the car and this will also help.

Once you have done that you will have most of the air out but there will always be some in there. As mentioned the Viper is a self purging system. As you drive a bit the air will come up. The level in the pressure bottle may drop a touch. Just refill back to the top seam of the pressure bottle. All will be good.

As far as temperature swings go, the Viper will have these. Under normal conditions, with a normal load and not "pushing" the car, expect the temperature to fluctuate between 180 and 220. There are a ton of factors. Ambient temp is the first obvious. Amount of air moving over the radiator. For example, the engine will run around 190 on the highway, in 6th cruising. In city driving the engine will cycle up and down more because of the fan being used to cool things down. The fan will come on at 205 to 210 and shut off at 200 degrees.

In the end, the system self purges so if you drive for 30 minutes to an hour, you'll see the pressure bottle level drop as you get the air out. Just refill and you will be fine. Once set, you see the level is maintained for a long time. Unless you have a leak, you may not need to add coolant again until you flush it again.

[SNKEBIT]

To a cool engine....remove the cap from the tank on the inner fender. Squeeze the upper hose on the drivers side as much as possible...use both hands. Air will bubble at the tank...then the level will drop. Add coolant...repeat..until bubbles do not appear when hose is compressed. (level will rise....but you don't want bubbles.)

This^^^^^ I also loosen the clamp on the heater control and let air out there while filling the coolant tank.

[mad prof]

Gentlemen, thank you to all. I will report with results

[JonB ~ PartsRack]

All the above is very good Gen 1994-2002 info, to which I add:

The 'best indicator' of having air in the motor is to squeeze-feel the UPPER radiator hose when engine is cold, and the surge tank ;radiator-cap' is OFF. If that hose feels full like a filled water-balloon, you probably don't have much / any air trapped in the motor.

But if it feels flaccid, soft, like and under-inflated football, it has significant AIR in the upper motor which much be purged as noted.

Also note that the trapped air in the upper motor is air-locked and CANNOT self-purge, since it would have to defy the laws of physics to move / siphon downward without a water-hammer pushing it as occurs in the surge tank. That 'uppermost motor air' must be bled thru the highest point in the system, which is the heater-core valve hose. Heater selector HOT-ON, hose removed, burp as noted and refill that heater hose with a skinny-funnel til no more bubbles emerge when squeezed.

Note: KEEP THE SURGE TANK ATOP THE RF WHEEL F-U-L-L and keep the overflow bottle in the nose 50% - 75% Full.

Good Luck

[Sybil TF]

Also note that the trapped air in the upper motor is air-locked and CANNOT self-purge, since it would have to defy the laws of physics to move
Note: KEEP THE SURGE TANK ATOP THE RF WHEEL F-U-L-L and keep the overflow bottle in the nose 50% - 75% Full.

Good Luck

Unless you have an AirLift tool...

[Matt M, Pa]

I do have an Airlift,,,,and still needed to do some minor burping on both cars....

[Sybil TF]

I do have an Airlift,,,,and still needed to do some minor burping on both cars....

Next time you flush the coolant use the Evan's waterless coolant. Did your t-stat have a hole in it for bleeding? Did you let the tool vacuum the air out until the coolant hoses were fully collapsed? Also I bought the Roe coolant hose with the bleeder valve on top and burped for insurance from there. Worked like a charm the first time. You have to keep an eye on the overflow tank. If it goes empty on you during the process it sucks air back in..... Since it is hard to get to we disconnected the hose from the plastic fill tank that goes to the overflow tank, hooked a funnel up and filled it 3/4 while I watched with a flashlight. Ran and bled with the bleeder on the coolant hose. Then removed the fill cap on the fill tank and you hear coolant being sucked. Hooked the funnel back on the hose and filled to the mark on the overflow tank and that was all. She runs 190 consistently even on 100 degree days.

I did upgrade to a later model electric fan/shroud and it already had a Fluidyne radiator in it. As far as I know it still has the stock t-stat but not sure. I'm considering buying the dual electric fan kit for more insurance. In case I get a blower

By the way what condition is your radiator in. Maybe it is gummed up?

[Matt M, Pa]

Thanks Sybil....I'm not sold on the waterless coolant. I've read conflicting reports...and use what Chrysler recommended.

No, I don't have bleeder valves installed, either. All stock....radiator is fine...no overheating or other issues. I changed the coolant as preventativ maintenance.

I've been using the Airlift for a good while, and yes the hoses collapsed. For refilling, I use a 5 gallon bucket so no air is introduced.

Both the Vipers needed a little burping...but not more than a couple squeezes. (In my other cars...the airlift worked perfectly....great tool.)

[daytonprowler]

On my '93, when I refill the system, I raise the front of the car up. Take off the radiator cap and fill the system through the heater hose back by the firewall. It's funny that you can hear the air being pushed out through the radiator. Never had a problem with getting an air bubble refilling it this way.

[Sybil TF]

Thanks Sybil....I'm not sold on the waterless coolant. I've read conflicting reports...and use what Chrysler recommended.

Old man has been using it for over 20 years and has never replaced a water pump, heater core or radiator when used.

Jay Leno uses it.

[bluesrt]

jay leno says he uses it because they pay him to say that..lol

[Sybil TF]

jay leno says he uses it because they pay him to say that..lol

Proof is in the pudding. People who knock it won't use it because they are tight wads which I get. If it was the same cost as regular coolant it would be used by everyone.