[EricZ]

I noticed today when i got to work that i heard some bubbling from the radiator. I went to look and it was spewing coolant out the overflow (i filled it up last night while doing some general maintenance). Even if it was overfilled it shoudln't be boiling. Could the thermostat i replaced five years ago be on its way out? It might not be opening enough and limiting the flow. When i am driving the temp gauge always stays below the halfway mark so i am thinking the cooling effects while driving are enough to keep the coolant from boiling over but when i park it has no cooling and therefore proceeds to boil over. I'm thinking it's either the thermostat or the fan clutch.


Any Ideas?

 

[rochmpr]

If it's been 5 years, then you definately want to replace the thermostat. But don't stop there, do a high pressure reverse flush of the block, check the radiator to make sure the tubes aren't plugged. Doing the fan clutch and water pump would not be a bad idea as well.

You should replace the anti-freeze and thermostat every couple of years as normal maintenence.

 

[EricZ]

The coolant is changed regularly every 10 to 12 months.(probably more than it needs). Water pump is about 12 months old and in good condition. I replaced alot of stuff when i did my timing chain. I'll do the thermostat first and hope that gets it! I will also go ahead and get the flush. Don't think i've ever had it professionaly flushed!

 

[TNToy]

<font color="yellow">It's normal for coolant to flow from radiator to the overflow tank & back again as the truck heats -but only a little. I would replace the radiator cap and thermostat(less than $10 for them at the Dealer - GET A GENUINE TOYOTA ONE! They work and fit perfectly) Cooling and ignition are the two places all my Toy mechanic friends recommend using ONLY factory components.

The first things I recommend to anyone who has overheating problems is this:

• Radiator Cap
• Thermostat
• Take it to a DIY carwash place and shoot the radiator with a pressure washer through the grille. Mine had a slowly plugged with mud, and the temp gauge dropped 1/8 to 1/4 of the gauge just from that!
• After you fix it, flush & replace the coolant with using DISTILLED water (Buy it at the gorcery store for chump chang)! It doesn't generate mineral deposits inside the radiator like tap water does.

</font>

[ 08-15-2001: Message edited by: MasterYota ]

 

[toylet]

When the engine is warm, feel the top radiator hose and compare it to the lower one, if the top hose is quite a bit hotter than the lower one, thermostat is probably gone. I would suggest replacing it regardless, if your truck overheated at all it should be replaced, I guess overheating can cause damage to it.
You really don't have to have it professionaly flushed, they have kits in almost any auto parts store for back flushing. All you do is cut one of the hoses towards the back of the engine, I'm not sure which one, the kit tells you, then put the T pipe in the kit in , and your done. You can also get a chemical flush, which is what I would suggest. I put a 4.2L YJ radiator in my truck and did both flushes, and you could drink out of that thing it's so clean.
Also, if the fan clutch is gone, get an elec. fan, my buddy gave me an elec. fan along with that radiator and it works great.
From what I have been taught, the rad. cap really only needs replaced if the rubber ring inside it is bad, if it is cracked there won't be good suction to pull fluid from the resivoir.

 

[TNToy]

Originally posted by toylet:
<STRONG>From what I have been taught, the rad. cap really only needs replaced if the rubber ring inside it is bad, if it is cracked there won't be good suction to pull fluid from the resivoir.</STRONG>

<font color="yellow">Close... The radiator cap has a spring and a seal on it. Basically it's a pressure relief valve. If the spring gets worn then it's not letting coolant flow into the overflow tank and back as it should be - if it's weak you can have a leak with even with a good cap seal. The radiator cap is like the thermostat. They simply get replaced by default whenever you have an overheating problem because they wear out every few years - so they are general mantainence you might as well do while you're there. Also, they're easy to replace, they cause most of your cooling problems, and they're CHEAP. As I stated before, go genuine Toyota - voice of bitter experience. It's worth the extra $5...</font>

 

[pickeledpigsfeet]

I had same proba while back. Replaced my rad cap and presto, it's fixed. THere was no visual sign that the cap/seal was bad, it was at least 4 years old though. Easy and cheap fix, try it if it dosent fix the problem your only out a couple of dollars.

 

[JackA]

Time to part that hoopty out. J/K <IMG SRC="smilies/biggrin.gif" border="0">