Question about 1998 Ford F150 Regular Cab

1 Answer

Coolant problem The temp. control goes up blows hot air then it will drop & blow cold air. no visible leaks, changed thermostat & cts. & flushed rad.

Posted by on

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    MVP:

    An expert that gotĀ 5 achievements.

    Novelist:

    An expert who has written 50 answers of more than 400 characters.

    Governor:

    An expert whose answer gotĀ voted for 20 times.

  • Expert
  • 81 Answers

Sounds like you might have an air pocket in the cooling system. This can develop, usually after a service, where the cooling system has to be opened to replace a water pump, thermostat, or other reason. When refilled, the air displaced by coolant has to go somewhere. In many cases, youll find that air is trapped in the highest place it can go...above the level of the radiator cap or overflow bottle. This can be a portion of the upper rad. hose, a heater hose, or a coolant line running thru various parts of the intake/throttle body area. What I do after topping up the system, is let the engine warm to normal op. temp./ W radiator cap still off. When upper hose becomes hot, you know thermostat is open. Now, if a bleeding device is not present, back off a hose clamp at the highest point in the system. Take a pair of pliers and twist the hose just enough to break the seal. You should see steam or drops escaping from your "breach". Once the steam stops and becomes all coolant, you have likely bled all air from the system. Top up radiator and coolant bottle to proper mark and close the system. (tighten your hose clamp) Check for leaks. Keep an eye on your system for a day or two, to insure no leaks are present.

Road

Caution! As with any task that involves opening the cooling system...Coolant and water can become very hot. Hot water and steam can be very dangerous. If you dont feel qualified to perform this task, let a mechanic do it!

Please Rate me by scrolling down to the colored flags and choose which catagory best fits my response.
Thanks.....

Posted on Feb 04, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Thermostat problems


your easy, that is caused by AIR Pocket in the engine block
the gauge can not read, air temps so if air is below the engine
coolant thermostat the ECT reads hot then air (cold ) repeats
you lost coolant and the number one reason for that is trusting
the silly side tank, (they fail easy)
never do that, on the next cold morning , dead cold
you take off the RAD cap. look down the neck, is it full of green
AF? id bet you its not.
the cab heater will never work with no engine heat, ever. so ......
never do the above on any hot engine.
also the thermostat might be bad and the coolant overheated
and blew out, so get a new STAT.
the flush the system, and refill with 50% AF.
or worse. lots of ways to overheat.... ask.
the side bottle only works, (called the expansion tank)
if never overheated
and the tube in side is not dropped off
and you never let it go dry, ever.

those facts and others are why we check the RAD directly cold.


Jan 16, 2014 | Jeep Compass Cars & Trucks

1 Answer

Problem with 2001 Toyota Carolla..... When driving, cabin heater blows hot air, and tem gauge stays normal. When stopping or idle, it blows cold air and temp gauge flucuates. After doing some research,...


There's a blockage some were as when ur driving the rpm is high so pressure is pushing hot water through when idling very low pressure u need to use strong flushing .agent and flush out your system also revirse flush if still doing it after this it will b ur main rad needs re coring not heater

Oct 25, 2013 | Cars & Trucks

1 Answer

2001 sebring blows hot air then after approx 20 mins blows cold air. Temp gauge inside car only goes up to about 1/4 mark.. any ideas? Had coolant system flushed.


Sounds like maybe a stuck thermostat. or a blocked heater core. Just cause the system was flushed dosent mean the heater core was cleaned out.

Dec 30, 2011 | Chrysler Sebring Cars & Trucks

1 Answer

What does it mean if the heat is blowing out cold air?


a list of things to check
1) check both heater hoses coming out of the firewall to see if both are hot, if one is cold try flushing out the heater core, than do a back flush, if that dont work check temp guage on the dash, temp guage is low, change thermostat, check for coolant leaks

Oct 03, 2010 | 1998 Chevrolet Blazer

2 Answers

Changed thermostat and added coolant but 1997


could be waterpump?
i was going to say rad fan,but if so heater would be hot.
lack of coolant will make heater core to blow cold,if engine heats up with full coolant,usually means poor or no circulation.
water pump?
run engine with full coolant,at operating temp.with rad cap off and look in rad cap hole and see if there is movement of water inside rad.
[rad fan will not come on if water is not circulating through rad water pump?]

Dec 20, 2009 | 1997 Chrysler Cirrus

1 Answer

The heat in my 1992 Jeep Wangler is not working.


The only reason it won't blow hot air is because the water is not getting to the heater core. Check to see if you have a heater control valve in one of the two lines to the heater core. If so check to be sure that is is opening and closing. If it won't open then you get no water flow in to the heater core.

Feb 04, 2009 | 1998 Ford F150 Regular Cab

1 Answer

Engine overheats when heater pipes connected


I think you could be right about there being air trapped in the system.
Or the heater core(radiator) is plugged.
Either way you need a pressurized radiator coolant pump to put the coolant in without air being trapped.
Although,i have seen it done by jacking the vehicle up high enough that the radiator was now higher than the heater core level, and then the coolant was put in.
But this is dangerous to try.

Jan 29, 2009 | 1999 Ford Escort

1 Answer

04 civic heater blows cold air at idle


you should have hot water on all rad. hoses when the motor is running at a norm. temp. the water is not going through the heater core like it should. you have cutoff valve bad low water are a stopped heater.try a hoter thermostat if none of the above are true.

Jan 18, 2009 | 2004 Honda Civic

1 Answer

1995 ford windstar overheat after replacing the thermostat


Let your engine warm up with the rad. cap off and see if the coolant level drops. and make sure your overflow is full. It blows cold air because there is no water getting to the heater core. And it shows a normal(ish) temp because the water needs to be touching the temp. sensor. I really do think there is air in the system and there is not enough coolant but hard to tell from here. Also as with overheating any time make sure to check your oil and look for any coolant as the head gasket seldomly holds together if the motor overheats.

Dec 22, 2008 | 1998 Ford Windstar

Not finding what you are looking for?
1998 Ford F150 Regular Cab Logo

243 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ford Experts

yadayada
yadayada

Level 3 Expert

60867 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

21949 Answers

Fordexpert

Level 3 Expert

5331 Answers

Are you a Ford Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...