Still overheating! -Damn!

[toyotatifft]

Well, it's summer again and I thought I had my over heating problem fixed, but not so. (My previous posts on this problem is here Biazzare Tacoma Overheating!) I started running hot again yesterday, but I'm not losing any coolant like I was before. My friend swears his Jeep used to do a similar thing, and it was the fan clutch that had gone bad. I'm not sure about my clutch, the fan seems to move just as freely when the engine is warm vs cold. The thing that gets me is that I run hot while driving 55mph. I would think that would put enough air through the radiator to do the job. Is it possible that I need the fan to be "enguaged" even while driving? This is getting irritating as crap! I hate riding around in summer with the heat on. I'd love to hear from someone who has had similar problems, or isssues with their fan clutch. Peace ya'll!

[Bakemono]

My '91 4Runner SR5 V6 had a small fan besides the normal belt driven one. It would run quite a lot during the summer when it was hot.
Perhaps yours isnt running.
Im thinking that when you are running at 55 mph, the engine isnt turning a lot of rpms so the main fan (the belt driven one) isnt spinning fast enough to keep the engine cool.
Im not sure if the small fan runs all the time when you are driving, or only when the engine is a little hot. I was stuck in traffic once on a hot summer day and I noticed the fan would run off and on.
How do the cooling fins on your radiator look? If some of them are bent or otherwise crushed, it might not be cooling as efficiently as it should.
Cap'n

[Rycam]

The fan is no issue after 30-35 MPH. At higher speeds the forward motion of the rad should is enough to cool the engine with a healthy cooling system.

If you have The Green Prestone Stuff in your truck, you may have clogged radiator fins. Toyota red does not do this as it does not contain jelly-like silicants.

Replace the radiator and use Toyota Red mixed with distilled water before you pop a headgasket. Radiator flushes are "feel good" chemicals that only delay the true fix. I have firsthand experience with this.

[toyotatifft]

Captain_Toyota: Thankd for the response. I've only got the one belt driven fan.

Rycam: Thanks for the response. Very interesting informantion. My coolant didn't get changed for the first 5 years or so when I bought my truck new. When I did change it, it was black and nasty. I used some Prestone cooling system flush and used a 50/50 mix of Prestone antifreeze & water in the system. I never had problems loosing coolant or overheating before this. If you have any more details on the "green Prestone stuff" I love to kow a little more about it. Thanks!

[Bakemono]

Ewww, you should have used the red coolant. I suggest you head down to a Toyota dealer and get some Toyota red coolant. That might be most of your problem right there, wrong coolant.
Cap'n

[toyotatifft]

I never knew there were these different types of antifreeze. I checked to see what I have been putting in it recently, it is Prestone Extended Life. If I understand what I've been reading, that shouldn't be mixed with regular "greens" because the pH is different and can cause problems. Either way it's going in the shop Monday to get a good power flush and have the coolant replaced. My mechanic said something about using some orange that is specially fomulated for deisel engines. What do you think about that?

[Bakemono]

There are different kinds of antifreeze. They have the normal green, DEX-COOL and red. Ive also heard of the orange coolant.
If you have a diesel and you know that you can trust your mechanic Id say go with what he says. I dont really know much about it though.
Cap'n

[Rycam]

I have heard of some sort of orange "diesel" coolant, and supposedley has the approval of Caterpiller. I have heard of some pink antifreeze that is used in Europe (BMW). I don't think some exotic coolant is going to be a viable option for most people. Motor oils and tranny fluids are compatible by Federal Law. This is not the case with antifreeze.

The fact is, Toyota Red is specified for your Toyota as it was designed to be used in bi-metallic engines (iron block/alumium heads), and not have the silicate problem. The most important thing is to mix the Green or the Red with distilled water. Perhaps a lot of probs with the Green is that 99% of the time it is mixed with tap water. Anyone who says Toy Red is just the Green Stuff dyed Red is clearly mistaken.

The only drawback to the Red, is its propensity to "find" leaks. My truck has old heater hoses, and the show signs of very slow leaks. My old Camry has none of the problems with Red. The Green Stuff does tend to plug tiny holes, like a "high cholesterol diet" clogs arteries.

Please let us know how the powerflush goes!!!! Keep in mind a new 3 core radiator from radiator.com is around $140, and a 2 core is even less. Water pumps are rarely an issue unless the bearings fail/leak/get noisy. The only other two major parts left are the thermostat and the radiator.

Hey, in all the confusion...have you replaced the thermostat? Buy only the Factory piece, or a Stant on severe budget. Avoid the AutoZone's generic line of thermostats at any cost. And by all means...don't delay the decision to buy a new radiator. These engines can't take high temps for long.

edit: I read your link. If you suspect a bad headgasket, have you looked at the individual spark plugs for color/cleanliness? I have heard that a moisture leak into a chamber can blast a sparkplug clean. Are there bubbles in the coolant ? Just a thought.

[toyotatifft]

I checked my owners manual to see what it said and it just says use the ethylene-glycol type anti-freeze. I can't decide if to try the orange my mechanic says or go get some red.

I replaced the themostat already, thinking it was the obvious component, but it made no change.

My mechanic and I both agreed that the small leak I had must have been in the head gasket area, but since we used the leak stop stuff he had it's been OK, which is fine with me right now. Pulling the head on this truck looks like more than I want to do this summer.

The strngest thing about this whole deal is that I can ride for 30 minutes or more at 50mph and the temp guage never moves...thne suddenly it will slwoly start to go up. Turn on the heater, and then it goes back to normal. It goes in the shop tomorrow morning so we'll see what happens.

[Hermit]

When you say over heating do you mean in the red or just a bit higher than normal? Does it actually over heat? The black coolant thing is caused by mixing other coolants with the red anti-freeze. It turns the coolant instantly black. You mentioned that you had a coolant service done? It is possible that there may be an air pocket in your cooling system somewhere. I have seen this problem many times. This little pocket of air is like having a hot spot in your engine. It can also move around the system as you drive and cause your gauge to climb into the hot zone.To check this problem do as follows:.....
When the motor has been sitting for a while not running and is cold take your radiator cap off. Start the engine and let it run to reach normal operating temp. Keep an eye on the filler neck and wait for the thermostat to open. It may take a little while. You can tell when the coolant starts to flow that the t-stat is open(you can rev the engine slightly as you do this to speed up the process). If there is an air pocket it should burp and you will notice a lower coolant level,just keep topping it off. Then replace the cap and road test it. Make sure your coolant tank is full also.
There are many other things that could cause this problem but I would rule out the air pocket thing first.
Something else to think about is I would never recommend the stop leak stuff as this could cause restrictions in your system in many places besides where the leak is. It is a great quik fix in a bind but sometimes does more harm than good.
Hope this helps!
HERMIT T-Tech

[toyotatifft]

I had the cooling system flushed yesterday and filled with the good Toyota red ($25 / gal...Ugh!) I ran around town with the AC on and it still started to run hot after a while. Hermit: It has been real close to the red zone before, but I try to throw the heat on before that happens. An air pocket may have been an issue last year...I could hear "gurggling" sometime when I'd switch on the heater but I don't think that's an issue right now. I know this sounds illogical, but my mechanic just had an issue with another vehicle that was running hot and it was due to a bad fan clutch. I've heard of several people so far who have replaced the fan clutch and that fixed their problem. We ran my truck at idle for 45 mins and the fan clutch never got tight and it was 90 deg outside. I agree, you would think that going over 40 mph should put enough air through the radiator to cool things down, but maybe not. Since it's a fairly easy thing to change, I'm going to do that next and see what happens. I'm not crazy about the stop leak stuff either, but it did work, for now anyway. Rycam: the flush went well, there was some sediment that came out, bit not much. I'll let you all know what happens with the fan clutch replacement. Any good links on where to get a good price on OEM parts?

[Rycam]

Originally Posted by toyotatifft

I had the cooling system flushed yesterday and filled with the good Toyota red ($25 / gal...Ugh!)

We ran my truck at idle for 45 mins and the fan clutch never got tight and it was 90 deg outside.

Rycam: the flush went well, there was some sediment that came out, bit not much. I'll let you all know what happens with the fan clutch replacement. Any good links on where to get a good price on OEM parts?

Yikes, I think the max I ever paid was around $15-17 at the dealer. I used to clip a parts counter coupon from a local dealer and get it for $9 a gallon.

I want to make sure we are on the same wavelength here....A fan clutch should never become tight. It is made to slip at speed and free up horsepower. Besides, if the clutch froze, it would be much more stressfull on the waterpump bearing. Too loose is no good either, obviously. Also always store a fan-clutch vertically (like it is installed) so that the silicone oil has no chance to leak out.

My bet is on a new radiator, IMHO. A new radiator works better in all conditions.

[toyotatifft]

Were on the same wavelength. I've yet to find a real good way to check the fan clutch operation....I've heard "just grab it", "tie kite string to it" and "stick a piece of cardboard in it". Using cardboard, I can stop the fan with a little effort when the vehicle is at normal operating temp, can actually then spin it backwards very easily before it resumes forward motion. It always seems the same to me, hot or cold. The OEM part was $108 on the web so that's not too bad. Granted, my mind says a radiator too, but my gut says this is just wierd enough to be it, plus it seems to have been it for others I've enocounterd. The clutch is also cheaper and easier than a radiator. No doubt, I'll prob replace every part of the cooling system only to find that a dead cricket in my dash was hold the temp needle up.

I've been thinking a lot about the physics of the airflow around the radiator when driving and do believe that a fast turning fan will very much increase the airflow through the radiator over what normally gets pushed through by forward motion. Either way, new clutch will be on by next weekend, and when it works I'll let eveyone know that they need to change their fan clutch even though it sounds crazy. If it doesn't work, you can say, "I told you so." LOL

[Hermit]

I just replaced the clutch fan in the wifes 97 nissan pathfinder. Hers was locked right up and robbed the engine of horse power as well as drank up the fuel like a thirsty hound after a rabbit chase. Plus it was noisy as hell.

The dealer wanted over $100.00 just for the clutch, no fan. I was told by all the local parts store that it was a dealer item only. Anyways, I searched the local bone yards for a nissan clutch fan and found one that was like new (Jeeze, I was suprised to see so many nissans in the junk yards!). Its been working great ever since.

You should check out the junk yards before buying a new one. Most are very easy to remove with very few tools. I stuck the one I found right in the 'ole tool box after I removed it. The cost? $0 dollars.
Check it out and good luck! Keep us posted! You definitely have me very curious at this point *S* !!

*HERMIT* T-Technician
LOOKING FOR A GOOD CHROME REAR BUMPER FOR A 91 TOYOTA DLX 4X4 PICKUP!!!

[toyotatifft]

I'm putting on a new clutch, OEM. If I get a junker, then if I still run hot I'll be wondering if the junker was junk, LOL. Nope, I've got money to spend on it and I'm going to spend it just for peace of mind and to remove all doubts. On my old Chevy I would probablly gone to the bone yard, LOL