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3.0 Doesn't Get Up To Operating Temp After Coolant Flush


waterran

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Hey guys,

I recently did a coolant flush on my 97 3.0. While I was doing the coolant flush, I replaced the thermostat with a new one from NAPA (OE temp). The original one seemed to be working, but I figured why not swap it out while I was flushing the system anyway. However, ever since then, the truck has trouble getting up to temperature when its around say 60 degrees or below. It will just get up to where the needle points right on, or just above, the "C" on the temp gauge and stay there steady. It will only get up to operating temp if I sit idling for quite a while, but then once I start moving again it drops right back down. Of course, it's worse when it's even colder, but thankfully it gets warm enough still to get heat. I'm not sure exactly what temperature the truck gets to, but I will hook up my scan tool next time I drive and see what temp it stays at now.

Anyway, what I'm wondering is, is this normal for the 3.0 with a nice clean cooling system to run a bit colder? I believe I'd read something before about 2.3's having this issue and people blocking off their radiator with cardboard to get heat in the winter. So I'm just wondering if it is common for 3.0's to have trouble getting up to operating temp with a good cooling system. Or, if I just got a faulty thermostat. I just figured I'd ask before I go swapping out the thermostat again or even trying to test the thermostat since either way I would need to take it out.
Solved? Air pocket? raise the front of vehicle off the ground. If air is pocketed somewhere, this will help vacate it. We used to do it on the French Simca cars.
 


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97Ranger3.0

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The fan helps control the temp of the radiator. if you have the switch on the outlet then the fan comes on when when the radiator alone can not provide enough cooling.

If the switch is on the hot side then the fan can potentially come on when the extra cooling is not needed, causing the engine to run cool all the time.
I went back and forth about where to locate the temp sensor but finally decided I only cared about the temp after the rad because if the rad was cooling I don't need the fan on. As well my Camry has the fan switch in the lower hose.
Those are both good points, I never really thought too much about it. For now I'm going to keep my current setup because I'm using a VW temp switch which doesn't kick on low speed until like 203 or 205 or somewhere in that range. I believe the OE thermostat is around 197, so if I were to move this switch over to my lower radiator hose I think it would kick on way too late. I would have to go with a lower temp switch, which would probably require me making or buying another hose adapter for a BMW switch instead. Maybe one day I will make the switch though if I ever see the need.

Also, I know we're getting a bit off topic here. But, how would you go about choosing what temperature range for the switch if it's in the lower hose? Like about how much of a temperature drop would you expect from the inlet to the outlet in a properly functioning cooling system?

I definitely don't have a problem with the fan overcooling. I have lights in my dash wired up to show me when the fan is on low and high speed. It doesn't kick on low speed very often even on hotter days, unless I'm idling for a while. And when it does run it probably only runs for around 20 seconds or so before it kicks back off. I don't ever really see the temp gauge fluctuate, but I've hooked up a scan tool before and watched the temps to make sure the fan was working correctly. It kicks on around 203 or 205 like I said, then kicks back off around 190 or so. And again, the truck never ran this cool until I did the flush and replaced the thermostat.

The easiest way of all, assuming your scantool can graph, is to graph the ECT (Engine Coolant Temperature) as the engine warms up from a cold start. If the thermostat is working correctly, you'll see a distinct drop in ECT when it opens. If the thermostat is stuck open, there will be no such obvious drop in the graphed line.

You might be able to detect it even if your scantool cannot graph, but it's harder.

Failing that, just feel the hoses while warming the engine. If the thermostat is working correctly, then the return line to the radiator should be relatively cold until the thermostat opens, after which it'll get quite hot, rather quickly. (You can still use a non-graphing scantool here to anticipate when the thermostat should start to open, based on ECT value versus the thermostat's set point.) If instead that return line gets slowly and progressively warmer, the thermostat is stuck open.

Pulling the thermostat should really be the last option, IMHO.
Dude, thank you so much. I never even thought about either of those. My scan tool is super basic so I can't graph it but I could try watching the temps like you said. And your idea about feeling the lower radiator hose makes so much sense but I would've never thought of that. I'm gonna try that when I get a chance soon.

Solved? Air pocket? raise the front of vehicle off the ground. If air is pocketed somewhere, this will help vacate it. We used to do it on the French Simca cars.
Hmm, from what I understand don't air pockets usually cause the opposite problem, overheating?
 

8thTon

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The 3.0 is a iron block engine that doesn't heat up as fast as some newer designs, but still it's always been that way - if something has changed, then it isn't right. To me the simplest explanation is a thermostat that isn't sealing well when it's cold. I've also had problems with junk new thermostats.
 

Rearanger

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Also, I know we're getting a bit off topic here. But, how would you go about choosing what temperature range for the switch if it's in the lower hose? Like about how much of a temperature drop would you expect from the inlet to the outlet in a properly functioning cooling system?
I set my temp switch using an installed digital gauge and sender to replace the basic factory gauge. So when the rad outlet temp gets to my 195* setting the fan comes on. You could use the ECT sensor reading that I think you said your scanner can do. Start with low temp and work your way up for desired fan activation temp.

My fan never turns on while driving, only idling.
 

gw204

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What part number did you end up with for the thermostat? Have you gone back and verified on Napa's website that you were given the correct temp?

Since the issue appeared immediately after you put in new coolant and a new thermostat, I'm betting on the thermostat being bad or you just ended up with the wrong one.
 

97Ranger3.0

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The 3.0 is a iron block engine that doesn't heat up as fast as some newer designs, but still it's always been that way - if something has changed, then it isn't right. To me the simplest explanation is a thermostat that isn't sealing well when it's cold. I've also had problems with junk new thermostats.
Yeah, the truck has never warmed up quickly, especially in the winter. But it always got up to the operating temp and stayed there in a reasonable amount of time. So I agree it probably was just bad luck with the thermostat. And it sounds like more than a few people here have had bad luck with getting bad thermostats out of the box.

I set my temp switch using an installed digital gauge and sender to replace the basic factory gauge. So when the rad outlet temp gets to my 195* setting the fan comes on. You could use the ECT sensor reading that I think you said your scanner can do. Start with low temp and work your way up for desired fan activation temp.

My fan never turns on while driving, only idling.
That makes sense. If I ever see the need, I can always switch it relatively easily to the lower hose. My fan usually only turns on at idle as well, unless I'm towing or have a lot of weight in the bed or something.

What part number did you end up with for the thermostat? Have you gone back and verified on Napa's website that you were given the correct temp?

Since the issue appeared immediately after you put in new coolant and a new thermostat, I'm betting on the thermostat being bad or you just ended up with the wrong one.
It was a while ago now, and I don't have the receipt or box anymore. I remember asking the guy at the counter though to make sure it was the OE temp and he said it was. But, I do remember the part number had 190 something in it. (The part numbers usually have the temp rating in them, like 5400-195 or 5400-180 so I made sure to check that). I do see that on NAPA's website, they have a 192 and a 195 degree thermostat. It's possible I got the 192 instead of the 195 (although when I looked elsewhere it said the OE was 197 :icon_confused:) but I don't think a few degrees would make that difference, especially considering it struggles to even get to 170 now when I'm driving lol.
 

19Walt93

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Often the "right" aftermarket part is one that fits in the hole on as many different models as possible and comes within a row of a$$holes of the specs. If you pull the thermostat and there isn't a chunk of something stuck in it, I'd get a Motorcraft thermostat.
 

97Ranger3.0

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I tried the simple test that Orca suggested, feeling the lower radiator hose while the engine warmed up. It was around 36 degrees outside when I tried this, and by the time the temperature gauge just started to move (just pointing to "C"). The hose was already warm. I checked again when the temp gauge was 1/4 of the way up, and it was already hot. I should've had my scan tool hooked up at the same time to see what exact temp the coolant was but I would guess probably only in the 160-170 degree range based on where the gauge was at when I had the scanner hooked up before. So I would feel pretty confident in saying that I have a stuck open thermostat. I'll order a motorcraft replacement and swap it out at some point and verify that the problem is fixed.

Often the "right" aftermarket part is one that fits in the hole on as many different models as possible and comes within a row of a$$holes of the specs. If you pull the thermostat and there isn't a chunk of something stuck in it, I'd get a Motorcraft thermostat.
Yeah, I've definitely learned that the hard way. When I first got this truck, I didn't know any better and bought my parts on ebay or from oreilly, and I got burned many times with crap parts. My dad always swore by NAPA and I've heard good things about them elsewhere too, so I switched to them. I've generally had good luck with their parts but I guess the lesson learned is to try and find the OE part when possible and then NAPA or any parts store with a good reputation as a last resort.
 
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19Walt93

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I usually have good luck with Napa, too.
 

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Keep in mind that Napa doesn't manufacture parts, they're just a retailer for the manufacturers, the only two stats I personally will purchase are Stant & Motorad........try to stay way from the offshore junk
 

97Ranger3.0

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Keep in mind that Napa doesn't manufacture parts, they're just a retailer for the manufacturers, the only two stats I personally will purchase are Stant & Motorad........try to stay way from the offshore junk
True, but NAPA carries different brands than say Advance, Autozone or Oreilly which often have the same brand of parts. In this case I'm pretty sure I remember the box they gave me at NAPA being a Motorad.
 


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