Yesterday I changed my thermostat because, for about a year, the heater in my truck won't work unless you are actually moving down the road or hold the gas at a high idle. Somebody told me it was probably because my thermostat was sticking, so I thought I would give it a try.

Now, with the new thermo, the truck is overheating quickly. I did notice a small crack in the top of my radiator, about an inch or so from the radiatior cap neck. The crack goes all the way through, because when it overheats it blows steam through the crack. Could this crack be part of the cause of the overheating problem? Can I fix it with a blow torch, flux, and solder? I sanded the area around it and it is copper, so I figure this should work.

This is really confusing me now:confused:

 

i had a crack in the top of my rad and i tried to fix it myself and all i succeded in doing was to blow the head to bits it wont be much to replace the rad or to have it pro fixed it will save you in the long run when i got the rad fixed the guy said that the core had become blocked and that is why it cracked so if you just fix the crack it will go again as the rad is totaly shot in the first place for it to crack.

thats what happened to me, but if you want to fix it you will need to braze it as solder is not up to the job.

 

I just had mine replaced this summer. It had the same type of cracks you are referring to. I told the shop owner to come take a look at my rig. As we were walking to my Runner he asked me what year 4Runner it was then HE proceeded to tell me where the cracks were before he even saw it. I thought I was dealing with Carnac!!! Sure enough, the cracks were where he said they'd be. He said the 4Runners and Toy trucks were suseptible to cracks along the top of the rad. I got mine replaced with a new rebuilt one - hey lifetime warranty. Hopefully my lifetime, not his.

 

I don't know how to braize, but I tried the solder. It adhered but cracked itself. I will be going to the JC Whitney catalog next.

By the way, on the overheating issue, I have now drained and refilled my system 4 times in the last 12 hours trying to figure this thing out. Finally, I took everyhting new out and put all the old parts back in. Surely, this would fix the problem...WRONG! Out of desperation I looked in my owners manual ( ) and found the system had an 11.1qt capacity. I don't know how much was retained in the block, but I was able to squeeze in maybe another 1/2-1 quart, and that took care of the problem. Next time I will keep track of how much I drain out:pat: Now I am contemplating whether I want to drain it yet again, and put the new parts back in, again!

By the way, check out this email I had to send to my Dad earlier today about my son helping me out...

"Would it be enought to simply say "At least Griff's first experience with electricity was only 12 volt DC"?

I layed out a towel over the engine and sat Griff up in the bay while I worked. I specifically covered up the battey and terminals so he wouldn't play with them. Every so often I would give him my ratchet to hold on to. All was well, we were having fun getting greasy together when KAPOW! he touched the ratchet to the + terminal and the power steering pump at the same time. He never cried, because I think he was more scared than anything, but he did tell me he had a "little owie on my hand". Luckily, a little mousse got his hair flattend back down before Janice returned from her shopping trip. I still don't know how I am going to explain why his right eyebrow hair won't lay down though..."

 

As I understand, those cooling systems need to be "burped" due to they get air pockets in them when you start draining the water. The local shop that did my engine work had a heck of a time getting the system to burp. Finally they burped it. Also, at this time I had my radiator replaced too. Pin holes and cracks.

 

the overheat prob could also be due to a blocked rad core ,
as for braizing it is the same as soldering but you have to use fluxed copper rod and a much hotter flame

 

Not to seem rude, but is the thermosat installed the correct direction? The larger pellet end of the thermostat should go towards the engine.

On the other issue, get a new radiator with the full guarantee.

 

I just went round and round trying to get my radiatior replaced. It was a csf with a LIFETIME warranty. It had a crack on top. The parts store that sold it to toyota collision (who put it in originally) said they never sold it to toyota. And so on. Long anoying story short: they ordered a new and I got it free of charge. I replaced it in 30min.

 

Thermostat in right? On the V6, it goes on the lower rad hose water neck on the block and the point goes to the radiator hose side. As for the radiator, try usinghttp://<a href="http://www.performan....com</a><br />
these are identical ins appearance and performance of an OE, you can click on year, make model, engine size etc, then click on order to get the price shipped to your door. (no, you dont have to buy then, just click "buy" to get the price. I've eused them quite a bit and I had each radiator at my house 2 days later!:beaver:

 

 

I have a 2nd gen Runner and I have a small pin hole leak by the filler cap of the rad.To me it seems like a lot of 2nd gens are having this problem.

 

My problem was that I just had not put enough fluid back into the radiator. I also have a pinhole leeak by the radiator cap and the heater still does not work unless moving. I am afraid I will have to replace the heater core...

 

I dont think it will be the heater but i would definatly change the rad out for a new or reconditioned one , if your rad core is blocked then it might cause a problem getting enopugh water in to it to fill it properlyalso fi it only works when you are moving could your water pump be on its way out?