Question about replacing fan clutch.

[loondog33]

Hello there. New to the forum, hope I'm not repeating topics but I did not find this elsewhere on the site.

My question is, I recently bought a Hayden fan clutch, as I need to replace the coolant temp. sensor. So I figure I'll replace water pump, thermostat, sensor, and fan clutch all at once as preventive maintenance. Well, as I was reading the instruction sheet that came with fan clutch it states: Do not replace fan clutch unless it is giving an check engine code. Is that just a disclaimer for people who think the ticking noise is an issue that deems replacement?

My truck has not shown any codes, but the engine temp. will sometimes drop below the 210 mark, especially when idling like in a drive-thru. I replaced the secondary air system, 02 sensors, thermostat, spark plugs (used ac delco's), and cleaned the throttle body last year. My truck is at 129,000 miles and everything I've replaced so far seems to be original factory parts so I'm sure the fan clutch is 10 years old.

I really do not want to have to pull the fan shroud twice or just wait till the thing breaks. What is the harm with replacing a fan clutch that is not throwing codes? I assume nothing overtly bad would happen. I just what to get in there and get it all done at the same time. Any thoughts or comments are greatly welcomed, Thanks for looking.

 

[KNBlazer]

If this is a serious post, then the only harm will be to your wallet.... the temp dropping on your dash can only be confirmed with a scanner... chances are your thermostat is stuck in the open position.... try taking it on highway speeds early in the am for a few miles when the outside temps are in the 40s or 50s... this would throw a P0128 code confirming your thermo is out....

Generally if funds are available a lot of people replace pump and clutch at the same time, mostly for peace of mind I would imagine....

 

[6716]

I haven't done the coolant temp sensor, so I don't know if pulling the shroud is required for that.

My original fan clutch went out under 100,000 miles. The second one started acting funny at 195k, and I replaced it when the water pump gave up at 210k.

If you like to wrench and have the cash ... well I guess. But if you like the truck and think you might hang onto it a while, you might have the shroud off a couple of times anyway.

You might be one step beyond preventive maintenance with this particular plan.

Happy wrenching either way!

 

[loondog33]

Yes, this is a serious post and thanks for responding. And no, I don't need to take the shroud off for the thermostat or the sensor, only the alt. But I'll be under the hood wrenching already and figured I'd get some work done during the summer because working on your vehicle in the winter around here doesn't fly well. I'm garage-less, so I have to get it in when I can.

I've had the temperature fluctuation since January-ish and I've had it out on the highway on cold days, no codes. However, I do get the SES light flash every great now and again, but it leaves no codes that my od II scanner registers. It flashes so fast I usually only see it in my peripheral vision and it's gone by the time I look down at the dash.

I noticed the fluctuation while in a drive thru in Jan, after I let my mother use the truck to travel to Arkansas (1000 mile trip total), and it has not thrown any codes. I'm not sure if it is the thermostat because it was just installed, Ac delco, about 10,000 miles ago, but I'm going to replace it anyway just to be safe. I do plan on keeping the truck till the wheels fall off so I like to keep things from becoming issues.

I've read through old threads at trailvoy and found people having similar issues who stated it was the temp. sensor and it threw no codes for them either. I do realize that is far from an accurate diagnosis, but it makes sense. The truck does have 129,000 on it and the previous owner did zero maintenance to it. That is why I had to replace the secondary air system. The previous owner drove with the secondary broke for quite sometime, which caused the plugs to foul out, both o2 sensors to burn out, and the catalytic converter to clog. I'm guessing the temperature sensor was also in need of changing at that point too but was over looked. I replaced all the thing I could but did not have money for temp sensor at the time. I imagine that the water pump and fan clutch could use a change at this point as well. My thinking is, why wait till it breaks to address it?

At 130 thousand miles, if the parts are still factory then the water pump and fan clutch are not going to last much longer either so I'm not really saving money by not doing it now. Better to change out parts now when the weather is warm than to be stuck outside this winter cussing myself for not doing now. Plus, I got a good deal on parts: fan clutch, thermostat, temp sensor and water pump only $208. All parts made in America to boot.
Thanks for the responses everyone.

 

[Sparky]

Well, for what it is worth my 02 still has the original fan clutch and water pump, at 200k miles. (That said I think my water pump may be starting to go as I'm getting a bit of a grind/rattle noise under the hood I haven't fully narrowed down yet)

If you've already got the parts, can't hurt to do it I suppose. Keep the old as a spare, just in case?

 

[KNBlazer]

Yes, this is a serious post and thanks for responding. And no, I don't need to take the shroud off for the thermostat or the sensor, only the alt. But I'll be under the hood wrenching already and figured I'd get some work done during the summer because working on your vehicle in the winter around here doesn't fly well. I'm garage-less, so I have to get it in when I can.

I've had the temperature fluctuation since January-ish and I've had it out on the highway on cold days, no codes. However, I do get the SES light flash every great now and again, but it leaves no codes that my od II scanner registers. It flashes so fast I usually only see it in my peripheral vision and it's gone by the time I look down at the dash.

I noticed the fluctuation while in a drive thru in Jan, after I let my mother use the truck to travel to Arkansas (1000 mile trip total), and it has not thrown any codes. I'm not sure if it is the thermostat because it was just installed, Ac delco, about 10,000 miles ago, but I'm going to replace it anyway just to be safe. I do plan on keeping the truck till the wheels fall off so I like to keep things from becoming issues.

I've read through old threads at trailvoy and found people having similar issues who stated it was the temp. sensor and it threw no codes for them either. I do realize that is far from an accurate diagnosis, but it makes sense. The truck does have 129,000 on it and the previous owner did zero maintenance to it. That is why I had to replace the secondary air system. The previous owner drove with the secondary broke for quite sometime, which caused the plugs to foul out, both o2 sensors to burn out, and the catalytic converter to clog. I'm guessing the temperature sensor was also in need of changing at that point too but was over looked. I replaced all the thing I could but did not have money for temp sensor at the time. I imagine that the water pump and fan clutch could use a change at this point as well. My thinking is, why wait till it breaks to address it?

At 130 thousand miles, if the parts are still factory then the water pump and fan clutch are not going to last much longer either so I'm not really saving money by not doing it now. Better to change out parts now when the weather is warm than to be stuck outside this winter cussing myself for not doing now. Plus, I got a good deal on parts: fan clutch, thermostat, temp sensor and water pump only $208. All parts made in America to boot.
Thanks for the responses everyone.

On sensors the general senses here is to use only AcDelco or GM genuine, compatibility issues have been reported by TV owners, while others have had no issues...

 

[Niklaus]

It is not always that a bad fan clutch will throw a code. Sometimes it may not fully engage, only partially, which will reduce your cooling.
If you replaced the thermostat you should've changed the sensor with it. Most people say that the gauge should read a solid 210 and any under/over then you have problems. It's not serious but if it's under then you are running rich and over.. well means you are over heating in most cases.

If all you have is a ticking sound with the fan clutch I don't see why you would replace it. Unless like the guys before me said, you have the money and want to. No harm though.

Generally water pumps would show physical signs if they are worn down like vibrating or rattling or squeaking the belt. If you want to check your water pump then you can also check the coolant flow and see if it is moving.

If you have dips below 210 then it is most likely the thermostat or sensor.

 

[loondog33]

I'm pretty sure it is the sensor with a possibility of the thermostat sticking, that is causing the temp dip. My fan hasn't really shown major issues other than it seems to be getting louder at times, but I also could be hearing things. I just want to get things done before winter hits just in case. Plus, I'll have some spare parts in case a buddy is in a pinch.

I honestly figured that there is no reason that installing a fan without ses codes would cause problems, but the instruction sheet had a disclaimer against such actions.

I wasn't saying my fan was clicking, the clicking is normal for the most part. I stated that the company most likely put that dumb disclaimer in because people were replacing fans because they heard the ticking of the clutch engaging and falsely assumed that it was bad. So they replace it and they still have ticking and the go through the whole return process. I just wanted some verification that there is no issue swapping out fan clutches.

Like I said its only two hundred dollars and a few hours of my own time. Not sure why everyone seems reluctant to do the same. An ounce of prevention is worth a pound of cure. Flush the coolant system, throw in a water pump, thermostat, sensor and fan clutch with possibly a new fan blade and I should be worry free for a while in the area under the hood.

Note on the ac delco only sensor, you're correct. The one I was going to get for $25 was an airtex, I'll have to change that to delco for a few dollars more. Thanks again y'all.

 

[KNBlazer]

I'm pretty sure it is the sensor with a possibility of the thermostat sticking, that is causing the temp dip. My fan hasn't really shown major issues other than it seems to be getting louder at times, but I also could be hearing things. I just want to get things done before winter hits just in case. Plus, I'll have some spare parts in case a buddy is in a pinch.

I honestly figured that there is no reason that installing a fan without ses codes would cause problems, but the instruction sheet had a disclaimer against such actions.

I wasn't saying my fan was clicking, the clicking is normal for the most part. I stated that the company most likely put that dumb disclaimer in because people were replacing fans because they heard the ticking of the clutch engaging and falsely assumed that it was bad. So they replace it and they still have ticking and the go through the whole return process. I just wanted some verification that there is no issue swapping out fan clutches.

Like I said its only two hundred dollars and a few hours of my own time. Not sure why everyone seems reluctant to do the same. An ounce of prevention is worth a pound of cure. Flush the coolant system, throw in a water pump, thermostat, sensor and fan clutch with possibly a new fan blade and I should be worry free for a while in the area under the hood.

Note on the ac delco only sensor, you're correct. The one I was going to get for $25 was an airtex, I'll have to change that to delco for a few dollars more. Thanks again y'all.

Doing all that work will probably be a 10-15 hr job....

it will be a lot less if you have the tools that speed up the process of removing

lower alt bolt (stubby 15mm ratcheting wrench)
temp sensor (slotted socket, I think 18mm)

 

[loondog33]

It's really not that much work. I don't see it being over 10 hours, for sure. I'll take the truck to have cooling system flushed before hand which will be less work on my part. I'm hoping no more than 5 or 6 hours tops, truthfully. I figure an hour or two for the fan clutch and water pump and same time frame for thermostat and sensor.

You nailed it with the stubby ratcheting wrench, that'll save 30 minutes right there, easy. And yes, I'm familiar with the sensor socket as well but thanks for the heads up. It would be a pain in the rear end without either of those tools.

I am having a hard time finding a reasonably price 36 mm wrench to fit the fan bolt, though. I'm not sure how well the rental fan clutch removal kit from auto parts store will work, the wrench looks generic and thin, like it might damage/strip that big nut.

I'm guessing I should also do a pcm reset after replacing fan clutch or the w/pump/therm/sensor, similar process as you do after cleaning the throttle bottle?

 

[kickass audio]

If you want to do all of them in the same shot feel free. I think they are more warning you that it isn't always the clutch assembly that goes bad on our platform. I had 1, the OEM go bad a little over 100k and I knew it was on its way out because it would randomly spin at full speed with the clutch out of nowhere and eventually set a SES light from it. Then I also had a very minor leak of radiator fluid from the water pump. It was an extremely small amount but it was leaking once in awhile so I knew it was needing a replacement eventually.

I am with the other members on here in strongly recommending you stay with the OEM thermostat and temperature sensor. The first time I had it replaced at a shop because I didn't want to screw with it in the middle of winter in my driveway they put a stant thermostat assembly in and a napa coolant temperature sensor. At 25k after that replacement I noticed I wasn't pegging up at 210 and sure enough a SES came on and when I used my scan tool it was for the coolant being below operating temperature. I took it back to the shop who did it the last time and had them replace the t-stat and temp sensor with an OEM one from the dealer even though it was just a faulty temp sensor I figured to nail both in the same shot since its right there. I had them leave the water pump alone the second time.

A little tip on how someone mentioned using a scan tool to look at the temperature, that really isn't a true test on our platform as we only have a single temp sensor that both the scan tool and dash read data from. The ONLY time the scan tool would be helpful is if you suspect a bad stepper motor on your temp gauge in the dash that is preventing it from getting up to 210 or a tick past it. Other than that if you have a SES and it is throwing a code for coolant temperature less than operating temperature then I will guarantee you that its a sensor/t-stat issue.

My recommendation to you is this.

1.) Check your upper and lower rad hoses for any nicks, cuts, cracks, etc and replace them while you're at it. You have a good amount of coolant being drained so why not nail them out at the same time?
2.) If you haven't drained the old antifreeze and put new in for awhile I would suggest draining it out of the rad and as much as you can from the engine. I personally didn't flush mine with water, I just emptied out the rad and used an air compressor on the upper hose to blow the water out of the lower hose on the block. It isn't a full flush but I have done that for years without any issues at all.
3.) As previously stated, I would really strongly advise you stay away from aftermarket temp sensors and t-stats. They are known for having weird issues where it doesn't open and close fast enough like an OEM one would or sense the temp fast and cause the SES to come on. Keep it with ac-delco for the parts on this.
4.) With you inquiring about performing a PCM reset, you do not need to do that in fact I didn't either time my coolant system was serviced. I would have no issue with doing that though if it came down to it because I clean my TB 2-3 times a year to prevent sticking issues. Resetting the PCM has no effect on the truck reading data from the new sensor or clutch. I would only recommend killing power if you are concerned about shorting out the positive stud of your alternator to the t-stat neck or engine while you pull it back a little to get to the parts you are replacing.
5.) For the fan wrench, the rental ones are not the best but they do get the job done. If you have access to an impact hammer you can make your life easier at getting that sucker off by keeping the drive belt on and using the impact hammer on the nut to spin it counter clockwise a few hits. Then you can take the belt off and use the wrench to unbolt it. The nut on the clutch is known for being a royal pain to get cracked loose so be ready for some fun.
6.) For the tool to get the temp sensor out, you really shouldn't need to get the special tool that is like an o2 sensor remover that is cut out to allow the wire to go through it. That is the right tool but I just used a normal open end wrench for it. If you never had the sensor off the actual tool of using the open end socket would probably be better for getting torque to break it free or if you feel ballsy you can just slice off the connection and use a deep socket on it to break it free from the block and when you put the new one on just use a regular open end wrench and be done with it.

 

[The_Roadie]

the previous owner did zero maintenance to it. That is why I had to replace the secondary air system. The previous owner drove with the secondary broke for quite sometime, which caused the plugs to foul out, both o2 sensors to burn out, and the catalytic converter to clog. I'm guessing the temperature sensor was also in need of changing at that point too but was over looked. ...

The SAIS runs only for 30 seconds on a cold start. Its only purpose is to get the engine into closed loop operation faster to reduce cold start emissions. Unless what was broken on yours was a permanently open exhaust solenoid valve, it couldn't possibly lead to bad O2 sensors or the too-rich mixture that would clog a cat.

Low coolant temp from a bad thermostat or incorrect coolant temp from a bad sensor could be the root cause of those things, though.

 

[loondog33]

The SAIS runs only for 30 seconds on a cold start. Its only purpose is to get the engine into closed loop operation faster to reduce cold start emissions. Unless what was broken on yours was a permanently open exhaust solenoid valve, it couldn't possibly lead to bad O2 sensors or the too-rich mixture that would clog a cat.

Low coolant temp from a bad thermostat or incorrect coolant temp from a bad sensor could be the root cause of those things, though.

I believe the solenoid was stuck open, because I had to replace the solenoid valve as well. I remember that because the shop could not use scan tools to check if valve was sticking so they had to test it the hard way. I had a reputable shop do the work to the SAIS and the mechanic/owner told me the open valve was what put all the extra stress on o2 sensors and cat converter. The cat converter then started with the sulfur smell and rattling 3 months after I replace SAIS, solenoid and thermostat. All replacement parts were ac delco.

 

[6716]

I am having a hard time finding a reasonably price 36 mm wrench to fit the fan bolt, though.

Northern Tool. $18. 5 on the shelf when I walked in the door.

 

[BrownHP800]

12" adjustble wrench fits the nut on the fan just fine. Leave the belt hooked up, put on the wrench and give it a quick whack with a hammer to loosen.

 

[loondog33]

Cool beans, I'll have to see if there is a northern tool near me or else I'll probably have to go with the adjustable wrench option.

I think I'll just buy all the parts to have on hand, but start by just replacing the sensor and flushing the cooling system and see how it goes from there.


Thanks for all the comments everyone. Nice to find a go to place for DIY answers.

 

[loondog33]

Hey Roadie, I read an old post of yours from TV, and you stated that slant and gates thermostats are comparable to delco. Do you think it is all that important to get 151-1006 from delco or would motorad or gates be fine. I'd like to by one made in the states rather than chinese made delco.

Thanks.

 

[The_Roadie]

I've never heard of a strong reason to prefer one thermostat brand over another. Certain items stand out in my memory as having brand sensitivity, like Delco O2 sensors and plugs. Hayden/Behr fan clutches. But on thermostats I don't recall any consensus of goodness or badness. And they're too cheap to obsess over and run a spreadsheet tally. And they're easy enough to change out (except for the intense annoyance factor) if you get a dud of any brand.

 

[loondog33]

I've never heard of a strong reason to prefer one thermostat brand over another. Certain items stand out in my memory as having brand sensitivity, like Delco O2 sensors and plugs. Hayden/Behr fan clutches. But on thermostats I don't recall any consensus of goodness or badness. And they're too cheap to obsess over and run a spreadsheet tally. And they're easy enough to change out (except for the intense annoyance factor) if you get a dud of any brand.

Thanks a lot. I appreciate it.