I wish to change My thermostat out because I beleive it is stuck open, because the van does not heat up unless I am wide open on the freeway for a good about of time. To My horror I can not even see it. I know where it is though. I wish to know if I can change this out without removing the alternater and the air cond. pump. Can this be done with a lot of patience and an ispection mirror or do I have to start unbolting all that stuff that is in front of the thermostat?

Mark

 

Start unbolting.

 

I'm guessing you cannot reach it from the drivers seat like I can on my '89?

I installed a Motorad T stat this last time. The little toggle valve made bleeding the air a no brainer, where my previous Superstants always took some effort to purge

 

No I cannot reach it from the drivers side. Actually last van was an 89 and they have moved the whole engine forward like the fords to afford easy access for swinging your legs by the dog house. This luxury I have been cursing as even plugs up front are a real bitch.

So, I did not know about bleeding can you give Me a lame mans lesson on that briefly. I suppose I should get that same custom thermostate then.

I do beleive I have to start unbolting and while doing so also change the serpintine belt. My next need for knowlege will be to learn how to change that belt as the alternater has to come off to access this crazy thermostat.

Thanks

Mark

 

Purging is more of an issue when the block has been drained. Just pouring more coolant into the radiator will not push the coolant up against the T stat and when the wax pellett is not submerged in the coolant it takes a lot longer to open. When it finally does, the system needs more coolant. There can also be issues with the vanes on the water
pump not pulling coolant, or pulling bubbly coolant through.

Some people just drill small holes in a T stat without a toggle valve to aid purging. The toggle valve on my AZ duralast Motorad made T stat probably leaks some, but not as much as a small uncovered hole, and probably slows down warm up somewhat.

 

You do know that's an old wives tale...correct? Coolant flows just fine across the bottom of the t-stat due to the heater bypass hose.

 

Until the t stat opens, it is the highest part of the cooling system.

If the block was drained, where is the air supposed to go when refilling from the radiator cap?

 

The air churns with the coolant as a result of the water pump running. Without the heater bypass hose at the base of the t-stat there would be an air-bound issue like you're picturing.

 

I Still do not see how the air can escape until the t stat opens. If the air cannot escape then you cannot completely fill the block via the radiator. If the T stat is not sitting in hot coolant, but hot air, it will take longer to open.

I've had my block drained twice. The first time I used a super stant, and barely got a gallon in the radiator and lower and upper radiator hoses, and after a while the upper hose finally got hot and the radiator drained faster than I could pour more coolant into it.

The second time with the toggle valved Motorad, I poured 3.5 gallons of coolant into the radiator, and after I turned on the heater for a while, it finally filled the flushed and empty heater core, and I got the remaining .5 gallons in the system.

Lots of newer vehicles have purge valves and will blow the head gasket if the cooling system is not bled before getting the engine to full temp.

 

So you are telling me I some how need to purge this system after I am done unbolting and rebolting the alternater so I can get to the flaming thermostat? I am going to change out top and bot. radiator hoses and the serpintine belt as well.

I have always just opened the systems on My vans replaced hoses etc. then filled it up got it hot and as soon as that happened it would take more coolant. Top it of and go!!

Master Mark