Engine not heating up to operating temp.

[oilpan49]

I have a 98 Ranger with the 2.5 and Auto tranny. I was just out a minute to run some errins. This was also the first time the truck ran all day today so I let it idle for about 30 seconds and then drive real easy, then proceed to drive as normal as the engine got warmer. Just a side note that the truck did have a coolant flush with Zerex green stuff just shy of a year ago when the thermostat was replaced with a fresh factory one. I've had bad luck with Autozones stats.

The weather up here has been very nice with clear skies mostly but it's just not reaching anything above 50 lately. Typical November weather up here. I noticed that my temp guage was not reading right in the middle of C and H. Here's a drawing to help describe. The periods indicated in the drawing help pinpoint where my temp guage is reading. Please forgive me as I'm not a computer artist

C_ ._____H This drawing describes where my temp guage was reading most of the time with my heater on.

C____.____H This drawing describes where my temp reades most other times without the heater on

My truck usually does this like I mentioned above with the heater on. Even when the heater fan is on low and the temp knob for the heater control set between Cool and Warm. My truck did this last winter too. Most other vehicles I have driven usually don't have a hard time heating up, even with the heater on. I know 4bangers take longer than most v6 and v8 engines to heat up but still mine shouldn't have any issues heating up.

For the heater to start blowing warm air, it takes about 5 minutes after start up.

I know this is lengthy but I'm trying to describe this as best as I can. Thanks,,,,,,AR

 

[pitzel]

When it's around 0 degC (freezing point of water), it takes a good 5 or 6 minutes for my 3.1L V6 to warm up to a coolant temperature of 60 degree C (the temperature required before the interior HVAC fans will start).

As engines become more efficient, warm-up times will continue to increase further. The new Mercedes Benz diesel-fired cars in fact have dispensed with heater cores and use electrical energy to heat the interiors for precisely this reason.

 

[grcmptrnrd]

My '00 w/2.5 and 5 speed does the same thing. The temperature range from when the temp guage starts moving to full operaing temp seems to be small. I'll be hooking a scan tool up this winter to see just how much it cools off. btw, the coolant temp sensor registers 191 in the summer, 194 after about 1 min WOT in 5th.

 

[berge]

quote:

---

Originally posted by Airborne Ranger:

For the heater to start blowing warm air, it takes about 5 minutes after start up.

---

that doesn't sound right. Even only idling for 5 minutes the coldest day of winter all three of my cars will have warm/hot air already.
defective thermostat sticking open maybe?

 

[Gary Allan]

quote:

---

that doesn't sound right. Even only idling for 5 minutes the coldest day of winter all three of my cars will have warm/hot air already.

---

Got an aluminum head perhaps??? I don't think AR does.

 

[tadaima]

partially stuck thermostat in my experience with 2 cars

 

[rpn453]

quote:

---

Originally posted by Airborne Ranger:
I know 4bangers take longer than most v6 and v8 engines to heat up but still mine shouldn't have any issues heating up.

---

I've found that smaller engines often warm up faster, since they have less mass and have to work relatively harder.

I'm going with thermostat problem on this one, assuming the rad fad isn't turning on.

 

[wlkjr]

I had the thermostat on one of mine stick open on an '89 Grand Am and would barely get the heat warm inside. After replacing it, all was good.

 

[tommyr]

my $.02 FWIW....I always check my thermostats on the stove in an old pot of boiling water to make sure they open properly before installing them. Also, are you sure all the air was purged out of the system when the coolant was replaced? If there is an air bubble somewhere, coolant may not be flowing properly which could give you a bad temp. gauge reading, or if the bubble is near the heater core, you won't be getting heat as you should. A service manual should tell you the proper way to make sure all the air is purged out.

 

[Mike_dup1]

I had a similar problem with a Chevy truck last winter, turned out to be a coolant leak. System was not reaching pressure. Once leak was fixed, its back to normal. Check the rad cap, maybe its not holding pressure anymore..

But, small engines can be a problem in colder weather. I had a S10 2.8L V6 and that truck was always running on the cool side in cold weather. Nothing I did to it helps except placing a piece of cardboard in front of radiator to limit airflow. That was the last small truck I ever owned.

 

[Ugly3]

quote:

---

Originally posted by Mike:
I had a similar problem with a Chevy truck last winter, turned out to be a coolant leak. System was not reaching pressure. Once leak was fixed, its back to normal. Check the rad cap, maybe its not holding pressure anymore..

---

What is the mechanism by which a lack of pressure would cause an engine to run cold?

 

[oilpan49]

I have to apologize for something I failed to mention in my first post. When the stat was replaced with a factory one and after the coolant flush, I did install a new radiator cap also factory. I wonder if my water pump is overcooling the engine possibly??

As far as the head material, I'm not sure of what it's made of to be honest. Tap tap tap, hmmmmmm what to do

Maybe a UOA could tell the tale, but GC hasn't been in there for not even 2000 miles yet?

Testing the stat is not a bad idea and I am considering it. Only beef I have is the stat on my engine is set back in the engine alittle bit so you have to dig around to get access to it. I remember when I first got my Ranger, that thing wouldn't waste time heating up. Under 5 minutes I remember the heater was warm but not hot,,,,AR

 

[berge]

quote:

---

Originally posted by Gary Allan:

quote:

---

that doesn't sound right. Even only idling for 5 minutes the coldest day of winter all three of my cars will have warm/hot air already.

---

Got an aluminum head perhaps??? I don't think AR does.

---

all three are aluminum head and block I believe. That makes a difference in warm up times?

 

[Ugly3]

I have never seen a car with a functioning t-stat that turning on the heater blower could drop the engine temp (at any outdoor temp).

Sounds to me like the t-stat is not seated correctly or not closing completely or there is no t-stat installed, or maybe someone drilled holes in the t-stat restrictor plate (some used to do that in the old days).

 

[rpn453]

quote:

---

Originally posted by Ugly3:
I have never seen a car with a functioning t-stat that turning on the heater blower could drop the engine temp (at any outdoor temp).

---

You obviously haven't seen too many -40 days!

quote:

---

Originally posted by Ugly3:
What is the mechanism by which a lack of pressure would cause an engine to run cold?

---

That is kind of odd. Maybe the engine wasn't cold though: maybe it just somehow reduced flow through the heater core?

[ November 15, 2004, 02:35 PM: Message edited by: rpn453 ]

 

[Ugly3]

rpn453 - You obviously haven't seen too many -40 days!

You are right, the coldest I have seen is -29F.

 

[Mike_dup1]

This is because once the radiator cap fails to hold pressure, a 50/50 mix of coolant and water will boil at 226 degrees Fahrenheit, instead of 265 degrees Fahrenheit, at 15 PSI.

So with a loss of pressure, the sytem does not reach opeating temp which can result in decresed heater performance as well.

 

[Ugly3]

quote:

---

Originally posted by Mike:
This is because once the radiator cap fails to hold pressure, a 50/50 mix of coolant and water will boil at 226 degrees Fahrenheit, instead of 265 degrees Fahrenheit, at 15 PSI.

So with a loss of pressure, the sytem does not reach opeating temp which can result in decresed heater performance as well.

---

I don't follow you. The operating temp is somewhere between 160F and 200F.