Vehicle heater problem

[Slow Ride]

Ok guys, I know this is more of a boating and trailer forum but my pulling truck is giving me an issue and in the past I have gotten good advice here so, I thought I'd take a shot. Here goes..... I own a 2011 Ford F350 King Ranch with 140K miles. I purchased it used. This week the heater has started working intermittently. I notice it works well when I'm driving 70mph on the freeway but blows cold when in town or slowing below 70 for very long. I'm not much of an engine man and know even less about these sort of components. I'm going to have the radiator flushed and refilled in hopes that it is simply old fluid and is not transferring heat properly or there is some sort of build up in the system that a flush might resolve. Other than that, I'm clueless. What else should I be looking for? IDEAS?

 

[dwco5051]

Re: Vehicle heater problem

Is your water temp gauge reading a constant temperature or is it fluctuating in sync with the road speed?

The good thing is that where you live you are not going to need heat for too much longer. So you have til next Fall then to fix it. Up here in Central PA I am looking as I write this of 2 degrees with a wind chill of -17. I might need my heater working still in June.

 

[Bondo]

Re: Vehicle heater problem

Ok guys, I know this is more of a boating and trailer forum but my pulling truck is giving me an issue and in the past I have gotten good advice here so, I thought I'd take a shot. Here goes..... I own a 2011 Ford F350 King Ranch with 140K miles. I purchased it used. This week the heater has started working intermittently. I notice it works well when I'm driving 70mph on the freeway but blows cold when in town or slowing below 70 for very long. I'm not much of an engine man and know even less about these sort of components. I'm going to have the radiator flushed and refilled in hopes that it is simply old fluid and is not transferring heat properly or there is some sort of build up in the system that a flush might resolve. Other than that, I'm clueless. What else should I be looking for? IDEAS?

Ayuh,... Have ya checked the coolant Level,..??

The cabin heater is the 1st to loose coolant at lower levels,....

 

[JoLin]

Re: Vehicle heater problem

Ayuh,... Have ya checked the coolant Level,..??

The cabin heater is the 1st to loose coolant at lower levels,....

My experience, too, from 'way back before the cars even had closed systems. Cold air from the heater was always the first sign that coolant was low.

 

[agallant80]

Re: Vehicle heater problem

I had this issue with my Tahoe. It turned out to be a mixing valve that was vacuum controlled. The point of this valve is so you are not putting hot water in the heater core when the AC is on. I would get hot air when I floored it or the RPM was very high but at idle or low RPM just cold air. Ford loves to use vaccume for everything, I would bet its a vaccume leak. Fine the coolent lines that run through your firewall to the heater core. The valve should be somewhere inline. It should be around the passanger side.

Heatercore bypass valve.

https://www.google.com/search?q=for...UTF-8#q=ford+vacuum+heater+core+valve&spell=1

From a quick google search it looks like its located by the transmission dipstick.

 

[MTboatguy]

Re: Vehicle heater problem

I have had this problem on many of my rigs, all Fords, it is the vacuum valve, I would bet my last dollar, they are a pain at times, but fortunately not all that expensive to replace, also keep a check on the coolant level, they don't have to drop much to change the temps in the system. But again, I would bet on that vacuum valve not working correctly.

 

[robert graham]

Re: Vehicle heater problem

It may well be that heater control valve, but you may also want to check/flush the heater core/exchange unit...take the coolant hoses loose from where they enter the heater core(usually back near the firewall) and stick the garden hose in it to flush/back flush that core....Debris from cooling system will accumulate in that heater core and stop/slow circulation of hot coolant....easy fix!...

 

[MTboatguy]

Re: Vehicle heater problem

With it being a 2011, I would be surprised if the heater core is plugged, if so, someone has been running some very crappy coolant in it, but I agree, it never hurts to have the system flushed and cleaned so you are starting out with a clean system.

 

[gm280]

Re: Vehicle heater problem

Just pray it is the heater control valve or a particle plugged heater core. I've seen that on a few vehicles before. But don't let it be the actual heater core :facepalm: they are the most PITB to change. While they cost little, $30 - $60 dollar ranges on the ones I changed, the amount of labor is truly unbelievable. I actually believe they start building most any vehicle with the heater cores and then add everything else on after the fact. I have to actually remove the passenger's front fender AND fender lining and then drill out some fasteners just to get to see the heater core... So be very thankful if it is only the fluid level and or the heater control valve. :faint2:

 

[robert graham]

Re: Vehicle heater problem

With it being a 2011, I would be surprised if the heater core is plugged, if so, someone has been running some very crappy coolant in it, but I agree, it never hurts to have the system flushed and cleaned so you are starting out with a clean system.

My Buick is a 1996 model and I've had to flush the heater core about 3 times....last time just a few weeks ago....but it's always surprising how much debris and scale that comes back out of it. While flushing with the hose always flush into the outlet and then into the inlet to loosen up the debris. Afterwards the heater always works noticeably hotter!....like I say, an easy fix!....

 

[hungupthespikes]

Re: Vehicle heater problem

+++on the back flushing. If you take it in for service, make sure they will do a back flush. My dealer wanted to change the heater core and they do not back flush, big bucks. The radiator shop always back flushes with service/coolant change and was under 40 bucks, plus guaranteed for one year. They always check and found/repaired a split vacuum hose too.

 

[britisher]

Re: Vehicle heater problem

Sometimes you can get an air pocket in the system and you get cold air coming out through the heater. This often occurs when the system has been disturbed and refilled with the heater in the off position. That means the heater doesn't fill with coolant and you get an air pocket. The solution to that is to 'burp' the system by leaving the radiator cap off while the engine warms up (with heater set to full heat) and allow air to burp out the hole. Then when the coolant begins to warm and rise in the tube you replace the radiator cap.

That said, heater matrixes these days have air blenders and distribution flaps, which are either rod controlled or vacuum tube controlled. If the vacuum tube breaks having gone brittle, then you'll lose that control. I had that happen on my old GM Safari's heating system. The rubber vacuum pipes were the originals and had just perished away. Several feet of new tubing and we were good to go. Others have indicated that could be your problem and I'm inclined to agree.

 

[lckstckn2smknbrls]

Re: Vehicle heater problem

Sometimes it's as simple as a bad thermostat.

 

[NewfieDan]

Re: Vehicle heater problem

Is it a gas or diesel. My '03 has the same problem at -20. When the engine is working no heater issues at that temp. When I slow down it cools off and I lose the heater. It still blows fine but very little heat from it. It's done it since I bought it new.

And unless I am towing, it gets worse the colder it gets. Took it on a highway trip ONCE at -30. Had to wear winter parka the whole trip.

No load=no heat at that temp.

 

[rbh]

Re: Vehicle heater problem

Remember the old trucking trick for winter travel, card board in front of rad with a few cut outs.
The more cut outs the cooler it runs.

 

[NewfieDan]

Re: Vehicle heater problem

Had that done. Didn't make any difference. When its that cold the truck had to be working at stay warm. With no load the engine wouldn't heat up. With a trailer, no problems.

 

[rbh]

Re: Vehicle heater problem

Had that done. Didn't make any difference. When its that cold the truck had to be working at stay warm. With no load the engine wouldn't heat up. With a trailer, no problems.

Was this in your FT Mac days?

Colder than a witches $!$ up there.

 

[NewfieDan]

Re: Vehicle heater problem

Yep it was, when I was up I. Ft. Mac. Down here, I don't have the same problems. Don't even have to plug, until this year. Normally on,by gets down to -10. This year it's a about 10 degrees colder than normal.

 

[generator12]

Re: Vehicle heater problem

I agree with the guys who posted above. A 2011 is almost certain to be clean after only three years. If the coolant level is normal, it's almost certainly the valve that opens to the heater core not opening.

 

[SteveMcD]

Re: Vehicle heater problem

Might also be the fresh air intake damper is stuck open/inoperative.