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1999 Plymouth Grand Voyager SE

10K views 12 replies 5 participants last post by  joeshannallie 
#1 ·
I recently replaced the engine in my van and the heat does not work. Just blows out cold air. The engine temp does not seem to want to work either. I found that I will be repairing the dreaded rotted rear heater hose today. I will be cutting the rotted parts out and replacing with regular heater hose. Seems alot have had to do that. If anyone has any ideas about the heat please reply soon.
 
#2 ·
Typical case of bad or missing thermostat. The thermostat goes in the bolt on fitting for the upper radiator hose and commonly fails so that the engine never warms up and therefore the heat never gets up to temp. A simple test is to block the radiator and see if the engine temp gauge will read higher when driving as the radiator will be much more inefficient blocked off.
 
#3 ·
Thank you

So a bad thermostat would cause the heat gauge to not work at all? It just stays on C and never try to move any at all. I will replace the thermostat in a day or two. Should have to begin with. It is time to take a break and walk away from it for a few days. Oh and why I am asking, I would like to know if you know where 2 wires go that is right with the main wiring harness connector? I should have took pics so I would have remember where they went. It would put you in the mind of 2 ground wires but I do not know if they are or not. Please reply soon.
 
#4 ·
Pretty good bet andyg was refering to your lack of heat issue when he talked about a bad thermostat. Even if the thermostat was stuck open, as he suspects, the temp gauge would eventually indicate a rise in temp. As you're thinking, a new ECT sensor should fix the gauge issue. What is the location of the harness the two wires are in?
 
#7 ·
Depending on the outside conditions (cold) and if he is driving the van or just idling it, the bad thermostat could keep the engine cold enough to keep the gauge on C. I think the gauge starts to move when the engine temp is around 100*F.
 
#12 ·
After looking over the schematics I found three solid grey wires but nothing to do directly with heating. One is a power feed to injector #5 from the PCM. Another goes to the right rear vent window motor. The last is the power feed to the cooling fan relay. I take it all that is working. Could these wires have been for an aftermarket accessory that was removed? Do either have power. Generally, ground wires are solid black.
 
#10 ·
I believe you may be looking at several unrelated problems. I believe you will find a vacuum motor on the hot water hose going to the heater, and unless I am mistaken, which is entirely possible, if that doesn't operate, you don't get hot water down to the heater core. I am assuming the heater worked before. Check to see if the vacuum hose is hooked up, it is a hard plastic line with a rubber nipple on it, as I recall. The see if the vacuum motor holds vacuum (if it worked before it should). The other problem is likely a disconnected or faulty temp sensor. Might have gotten damaged in the excitement of changing the engine. Can you put you hand comfortably on the top heater hose or top of the radiator, about 5 minutes into driving? Careful, but you should know by that if it is getting hot enough to register and if the thermostat is opening well. Hope this helps.
tcwagner1
 
#11 ·
So, what was the result?
 
#13 ·
I looked at another van with the 3.8 motor and everything is identical to mine. The 2 wires were attached to the engine block near where the transmission dip stick is attached to the block.
I cannot get the heat to work. It only blows cool air. I have changed the thermostat, the engine coolant sensor(near the thermosat housing). I have checked everything that I can think of. I also had to replace the heater lines going to the rear of the van. They were rotted. I cut the rot out and replaced them with regular heater hose. Also the cold and hot gauge will not work. The top radiator hose gets very hot. If anyone has any suggestions please reply soon.
 
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