Hi!
Ive done alot of searching but i cant find anything that can help me out here.
I got an rew engine in a FC shell. It has FD waterpump, custom rad and no AST etc. Ive made a pressure cap like the FC-setup.

My temperature readings are never above 90Celsius but when i turn the engine off i can hear boiling sounds from the engine, and the entire engine "feels" hot (crackling sounds etc)..
It seems to be air, but i cant figure out where it is and how to get rid of it. I got heat inside the car and the rad does its job. Ive got new waterpump and tried different Tstats (also without tstat)

Anyone got an ide? I HAVE searched!

Regards,
Sindre

 

It might look like "just another overheating-thread" but the reason why im asking is that the only sign of boiling i got is the "boiling" sound in the engine. my temps are all fine.
I can also add that this is a newly rebuilt engine, but no oil->water, water->oil or strange smoke.

 

Do you have electric cooling fans, or an engine-driven fan? The reason I ask is that in my FD, I would often hear mild boiling in the engine at shut-off when I still was using the stock FD thermoswitch (fans on at 221F) for the fans. When I switched to the FC thermoswitch (fans on at 205F) the boiling at shutdown went away.

In the stock FD, mild boiling sounds at shutdown are common.

Also, running without the stock Mazda thermostat is not a good idea. Either an aftermarket t-stat or no thermostat will allow water to recirculate through the warm-up passage in the thermostat body even after the engine is warm, reducing cooling efficiency, and sometimes causing overheating. Running no thermostat at all is a very bad idea, since the lack of restriction reduces coolant pressure in the block, causing localized boiling and hot spots.

 

Thanks! Im running el-fan with 88Celsius switch. Removing the Tstat isnt a solution, just had to check that it wasnt the cause.
So if my temps are fine and i got almost 9-10L of liquid i should`nt worry about the boiling sound? Ive heard other telling me its common, but since ive never heard it on my 13bRE and 13bT engine i didnt really belive it.

Maybe a stupid Q, but can a failed twinturbo cause overheating?

 

I don't know how much coolant your system should hold, so the fact that it has 9-10L in it doesn't mean anything to me.

I don't think a failed turbo would cause boiling sounds, but if it failed such that it restricted exhaust flow, then maybe it would cause hot spots and boiling would be possible.

Also, what pressure coolant cap are you using? 13psi (.9 bar) is recommended for the FD, but a higher-pressure cap (1.1 bar) will raise the boiling temperature and decrease boiling. However, it puts greater stress on the hoses, coolant o-rings, etc.

What coolant are you using? Standard ethylene-glycol? If so, what antifreeze-to-water ratio? More A-F in the mix will raise the boiling point temperature, but at the expense of lowering cooling efficiency (lower specific heat and lower heat transfer coefficient). BTW, it is highly recommended to use only distilled water mixed with the antifreeze to keep contaminants out of the system.

 

I'd also check for air trapped in the system. Get one of the Lisle funnels to help burp all the air out.

Dale

 

BTW, this is what I'm talking about

http://www.denlorstools.com/home/dt1..._kit_wext.html

Dale