I am about to change the thermostat and was wondering if I should flush the system with coolant flush stuff before or after changing thermostat.

Marc

 

do it before the swap... that way you know the t-stat is clean when your ready to button it up.

 

Update! Did the swap and the flush. Since then, the heater blower does not squeal. but still blows cold air. did not notice leak around stat housing when I did the swap.

 

it could be the valve that controls flow to the heater core, or you have air in the system. turn the heater control to full hot and postion the van so that the radiator neck is the highest point, and re-fill while it's running and warmed up. make sure you leave the cap off when it's cold before you start. you can squeeze the lower rad hose to help move coolant thru the system... that is said to help in removing air bubbles.

 

Still can't find the coolant leak at this point is it safe to assume that it could head gasket?

 

I tried looking thru your posts but couldnt find the answer to this... did you ever swap the cap? do a pressure test on the radiator? could your radiator be leaking at the top so the coolant is evaporating off under pressure?

I would say if the above has been done/checked, do a leak down test and see if you get any air in the cooling system.

 

I had a leak down test done today and found out that the lower intake manifold gasket is leaking. So I am going to work on it this weekend and not having done this exact repair I want to make sure that I have everything ready. Besides the gaskets is there anything else I am going to need?

Thanks
Marc

 

depends on what your planning to do... here are some DIY's writeups that may help.

plenum
https://dodgeforum.com/m_249261/tm.htm
if your doing the plenum gasket... use a felpro replacement gasket. better than the mopar one which still leaks over time.

water pump.
https://dodgeforum.com/m_224411/tm.htm
dont forget a new bypass hose. and use distilled water... prevents corosian inside the motor.

 

From wat the shop said, it was the lower intake manifold gasket that I will be replacing.

Thanks
Marc

 

yup, plenum... use a felpro gasket.