Intermittent Heat - 95 Conversion Van
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Intermittent Heat - 95 Conversion Van
OK guys... this is a weird one. I've read everything in this forum about heat system malfunctions and haven't hit on a solution to my problem....... yet!
Here goes. Last July, my radiator went up. Being the dutiful mechanic that I am, I replaced the radiator, water pump, thermostat and serpentine belt while I had it all apart. About 2 months later, my front heater core sprung a leak, so I replaced it too. I noticed that the engine temperature gauge fluctuated more than it had in the past, but I attributed this to a less sensitive thermostat.
When the weather turned cold, we began to notice that both front and rear heat worked intermittently. It seemed like a water flow problem to me. The hoses feeding the heater core would be cold, then hot, then luke warm. I thought maybe the thermostat was the culprit so I got another new one and put it in... with the same result. I checked the cold air damper door at the heater box and it works fine (opens when set to cold, closes when set to hot). After the new new thermostat, the heat seemed to work, but only marginally. This week, it got worse... ie, it was cold cold.
I got into it again today. Again, the water flow seems to come and go. I drove the car and it gave luke warm heat. I also had warm air from the rear ceiling ducts. Then, as I was driving, it seemed to go cold, even though the engine temp was at mid normal range. I went home and drove up on ramps to check the plumbing that feeds the rear system. The pipes were luke warm, but as I let the engine run, they got hot again.
This is driving me nuts. I'm sure I have a water flow issue. The system has clean fresh antifreeze (50/50) with no crud in it. The only thing I can figure is:
1. Two bad thermostats (seems unlikely)
2. There is a malfunctioning water valve somewhere
3. There is air locking going on somehow
4. Murphy is real but invisible
This is a 1995 E150 conversion van with front and rear heat. Sorry about the long post, but I didn't want to waste your time on things I already tried.
Its getting cold... this is my wife's car and she thinks I can fix anything! HELP!!!
Thanks,
Curt Russell
Baltimore, MD
Curt.Russell@Comcast.net
Here goes. Last July, my radiator went up. Being the dutiful mechanic that I am, I replaced the radiator, water pump, thermostat and serpentine belt while I had it all apart. About 2 months later, my front heater core sprung a leak, so I replaced it too. I noticed that the engine temperature gauge fluctuated more than it had in the past, but I attributed this to a less sensitive thermostat.
When the weather turned cold, we began to notice that both front and rear heat worked intermittently. It seemed like a water flow problem to me. The hoses feeding the heater core would be cold, then hot, then luke warm. I thought maybe the thermostat was the culprit so I got another new one and put it in... with the same result. I checked the cold air damper door at the heater box and it works fine (opens when set to cold, closes when set to hot). After the new new thermostat, the heat seemed to work, but only marginally. This week, it got worse... ie, it was cold cold.
I got into it again today. Again, the water flow seems to come and go. I drove the car and it gave luke warm heat. I also had warm air from the rear ceiling ducts. Then, as I was driving, it seemed to go cold, even though the engine temp was at mid normal range. I went home and drove up on ramps to check the plumbing that feeds the rear system. The pipes were luke warm, but as I let the engine run, they got hot again.
This is driving me nuts. I'm sure I have a water flow issue. The system has clean fresh antifreeze (50/50) with no crud in it. The only thing I can figure is:
1. Two bad thermostats (seems unlikely)
2. There is a malfunctioning water valve somewhere
3. There is air locking going on somehow
4. Murphy is real but invisible
This is a 1995 E150 conversion van with front and rear heat. Sorry about the long post, but I didn't want to waste your time on things I already tried.
Its getting cold... this is my wife's car and she thinks I can fix anything! HELP!!!
Thanks,
Curt Russell
Baltimore, MD
Curt.Russell@Comcast.net
Senior User
Joined: Jun 2004
Posts: 170
Likes: 0
From: The Netherlands, Europe
May be a long shot, and don't feel patronised, but is there sufficient water (fluid) in the system?
How else could you get those cold spots? Just no water? could / should you bleed with a rear heater?
Cor
How else could you get those cold spots? Just no water? could / should you bleed with a rear heater?
Cor
Junior User
Joined: Jul 2003
Posts: 53
Likes: 0
did you inspect the insides of the heater hoses for deterioration? could cause heater core partial blockage. You could try blocking off your radiator with some cardboard to see if the heat improves, thus eliminating a bad thermostat. Also, a faulty water control valve or vacuum leak to the valve could be the culprit.
5th Wheeling
Joined: Nov 2004
Posts: 44
Likes: 6
Sure sounds like an air lock to me....
My race car has a rear mounted radiator, so there is 23' of extra "radiator hose" running through the car. It is EXTREMELY sensitive to air locks when refilling it and I get the same symptoms that you are describing....
On my car, I added a schrader valve at the 2nd highest point in the system to bleed it out, not sure what you do on your van...
HTH,
DaveW
My race car has a rear mounted radiator, so there is 23' of extra "radiator hose" running through the car. It is EXTREMELY sensitive to air locks when refilling it and I get the same symptoms that you are describing....
On my car, I added a schrader valve at the 2nd highest point in the system to bleed it out, not sure what you do on your van...
HTH,
DaveW
