Working on the wifes van here. She lost her heat the other day. Thought maybe the thermostat went so i replaced that and flushed the system in the process. Drove it home but still no heat. So this morning she took it out and it overheated pretty fast. I squeezed the upper hose shut while the van was ideling and slowly opened it up, definitly no coolent flow, I am thinking the water pump went out, anyone got any other ideas???

 

water pumps going bad is pretty common from my understanding... cheap fix as well

I can think only of the coolant level itself being low, or there are traveling air pockets from your thermostat swap and flush that u didnt get out... Or your new therm is sticking (common too, especially a cheap one, get a stant)

maybe a clogged radiator?

 

heater control valve working? is the switch really opening the ducts to allow heat in?

 

DR,

A few more questions...

Are you sure of the belt routing? Id est, is the pump definitely turning the correct direction?

That "grunge" you cleaned from the cooling system - is it all out? There may be some of that clogging the heater control valve or heater core itself, rendering it useless. Have you tried reversing the heater hoses at the core to establish flow? Or back-flushing the core with a garden hose with the lines removed?

Is there a way to manually operate the heater control valve? If so, you can also flush that through to be sure it is clear.

I wish I had more data for you, but unfortunately, I don't.

 

Unless this is a fNord focus with a plastic water impeller you should have coolant flow even if the pump is bad.

It soundslike you have a air pocket or like Vader said "grunge" blocking off passages and possible plugging up the new t-stat.

Is there an air bleed valve on the t-stat housing???

 

Thanks for the help guys.......i think i got it. Before i went to all the trouble of changing over the water pump, i took the "new" thermostat out and threw it into a pot of boiling water. And it wouldn't open Stupid me, i should of known now adays you have to buy two thermostats to get one good one(since this is the second time in a row i got a "new" thermostat that was defective). Anyways threw in a new stat put some ZEREX radiator super cleaner in and started it up ,temp rose up half way and stayed there , felt the vents and started to feel warm heat after about 10 minutes,then all of the sudden it went to cold to warm to luke warm to cold so i shut the engine off. Just in time to hear two gallons off anti-freeze bounce off the pavement. The van has heat in the rear and the clamps that hold the lines to the under carriage rusted to the lines and erroded away .There are two clips about a foot apart and both of them have huge holes in them. Evidentally those huge holes had gunk clogging them and that cleaner stuff did its job, to well. I guess i am just going to get a foot and a half of small heater hose and some hose clamps and fix it that way for now. I think i'll be alright then. Just kinda wondering if a leak like that would make the heat go from warm to cold like that. Never hurts to do the smart thing and recheck things, saves time and money. Thanks

 

The big temperature drop was likely an air pocket in the system rtaht was released when the thermostat finall opened. That's fairly common. Most cooling systems have a bleed procedure to minimize that, but it's always a good idea to monitor coolant level for several days after a service like that to make sure all air is dispelled and the system is filled.

 

Well, that didn't work......... i replaced the broken line with some heater hose , let it warm up while the heat was cranking, after about 10 minutes i felt luke warm air coming out of the vents. So i revved the engine and the air coming thru the vents was getting warmer, then all of the sudden cold air just came out. Explain that anyone. Looked at a Haynes manual and unfortunatly the belt is on right.

 

And is the cooling system still full?

 

yea...this time it didn't leak out all onto the ground. Gonna try back flushing the heater core next i guess.

 

It does sound like an air pocket. This is the very reason we vacuum fill all modern systems, especially ones with rear heat. The lines back to the rear heater are known for trapping air in the system and causing exactly what you describe, warm, luke warm then cool air.

 

What's the best way to get rid of air pockets then ??

 

Since it's a van, turn it on its roof.

If that isn't an option for you, you can keep filling the system and run the engine with teh cap removed. It also helps if you can make the radiator or expansion tank the highest part of the system by parking on an incline, using ramps, or jacks and stands.

Remember that if you're using tap water, there will be air disolved in the water, and more air bubbles will generate when the coolant reaches about 170-180°F and the water gets deaerated.

Fun, isn't it?

 

Can't say that it is Vader, i have this to fix, the door handle on my service van totally broke off on the drivers side so i have get in thru the passengers sideso that's next on the agenda meanwhile for the camaro, i have a brand new set of acell 23 lb fuel injectors, a holley fuel pressure regulator , a 5" rear spoiler and a set of sub frame connectors to put on.....of all 3 which one would you think i'de rather be working on .. Thanks for the help Vad i'll try what you suggested.

 

Additives and crap can clog up a heater core fast. Not saying you used any but.

If you take the van or car to the DIY car wash. Unhook the heater hoses and use the blaster wand to do a reverse flow of the heater core. Ive done it to just about every car I have owner and got even better heat, when the heat was fine before.

Kind of a general maintenance trick I do to every car I buy.

But if your over heating its probably the pump.
First signs of a bad pump is no heat.

 

Overheating problem is gone...just a lack of heat now.