My block's been blown for almost half a year and after trying 6, 7 bottles of various brand of block fixes, I threw the towel in and put a small deposit on a front cut. Since I'm going to pick it up tommorrow, my friend and I gave it one last try. We removed the thermostat and poured in two cans of Whiz block seal, idled the car for 15 min and drove around for half an hour. We let her sat for 5 hours then took it out for a 30km ride with a flatbed following ready to pick her up when the engine quits. Amazingly, the coolant temp stayed constant throughout. The Block Seals seems to have done the trick! I did a radiator pressure test at 1.1 bar and apart from the gas leak from the radiator cap, there's absolutely no water leak from under the car!!!!!

Fellas, can I be sure now the leak is definitely fixed? If not, are there other tests that I should do before forgoing my deposit on the frontcut? I've also got a spare disassembled block sitting in the garage waiting for a rebuilt but this can be my next project now

 

No. If it happens again, which it very well might, replace the engine and sve yourself some headaces.

 

Those who've used Block Seal and find that it works, how long have your block seal job lasted? Anyone out there with a job that lasts for LESS than a year?

 

That's a good idea

 

That crap ruins the radiator, trashes the motor and can waste the water pump etc. Do a search...

 

This is coming from a true believe of CRC Blockweld as I am still running it right now. When I did my searches I found nothing but positives when it came to the use of it...the only downfall of a copper block weld treatment as "pomamferrari" posted is that it does in fact clog the radiator...

So what if you screw up your a stock radiator your water pump, overheat the engine and it dies on you?
(it doesn't trash your engine cuz RX7.com says so...I specifically asked if it would affect the engine in anyway when I brought it for a rebuild and their answer was "NO"),

the way I see it, it's better to spend $50 on a used rad and replace your waterpump when you do the rebuild...If it's gonna let your engine last a few more thousand miles then go for it cuz your engine is dead at that point anyway...I have been running CRC Block Weld now for almost 1k miles @ 12psi of boost and it's holding together nicely while I stash my pennies away for a rebuild...

My only suggestion is that if you have a nice aftermarket radiator like the PWR that you Aussies down under produce I would take it out and run your stock one and clog that one...when you get your rebuild go ahead and put your aftermarket back in.

Good luck!

 

It's a temporary fix at best and you never know if or when it will fail (unreliable) and it screws up your radiator. You are going to have to fix it anyhow why do it 1/2 azzed?

 

Very satisfied with yesterday's test drive, I took the car out for another spin this morning. Another 30kms with occassional boosts and everything's fine and well. I parked the car for half an hour, had my breakfast, restarted it with no prob drove 2kms and the Add Coolant light lit up. Half a km down the road, water's erupting from the coolant tank. Luckily I was very close to my friend's house so I stopped and let her cooled down for an hour, added water and pressurised the radiator tank to 1.3 bar. No leak! Pressurise it to 1.5 bar and the needle stayed still for more than 2 minutes. I'm baffled.

When I attach the pressure guage to the radiator and crank the engine cold, the guage builds up to 1.5 bar pressure. Does the pressure come from the water pump being cranked or a sign of air getting into the coolant system?

 

sounds like compression leaking into the coolant system....(coolant seals gone)....

 

How can it be considered a 1/2 azzed job if the next best thing to do is pull the engine?...this fix is something of last resort...I don't believe he should pull the engine if he has good compression and it pulls a good vacuum at idle (at least 15 mmhg). There are some block sealers out there that just plain suck....I used AlumAseal and it lasted for about 30 miles (boosting like crazy though)...If you can get a hold of a sealer that is copper based then that's what you wanna do...

 

They don't sell CRC or K&W Copper Block Weld over here and I've searched the net for an online vendor of the stuff without avail. If you know of any CRC vendor that does mail order, please let me know.

 

I would do a search for the company site and e-mail them with your situation and see if they would be willing to mail you some...Seems you will probably pay about $40 USD in shipping plus the cost of the product...about $4.50 per bottle...The treatment requires two bottles but I would go ahead and buy 4 bottles just incase you loose your coolant drain plug and have to refill it (yup, I did that while driving)...Hope this stuff works for you...It's holding together nicely for me while I am saving for my rebuild...

 

thanks for all your useful responses. Is there a test to determine whether my radiator is clogged by the half a dozen or so bottles of block seal that I've stuffed down it?

 

I don't belive so...Probably just pull it and run a hose throught it...and check to see if it flows well...