went for a test drive in my supercharged sa today. trying to work out the a/f ratio and timing settings when all of a sudden the coolant overflow container starts boiling and theres steam everywhere! what would cause the coolant to boil like that?

 

overheating

 

Where was your temp gauge? Hopefully you just got it a little hot and shut it down before the engine had a chance to cool down and stabilize. On the downside, you may have blown a coolant seal. Start the engine back up, if you have bubbles in the radiator, save up for a rebuild kit.

 

damnnn.
i just drove it for a couple of minutes before it happened.
the engine was on when it started boiling and i shut it down real quickly afterwards.
how would i check for bubbles?

 

open the rad cap start the car and if bubbles are pouring out where you can see coolant flowing then its as trochoid said, BUT be careful opening the cap if your car is still warm, pressure stays in the system for a bit.

 

ahh ill let the car cool down a bit...
damn might have to rebuild it soon.
gonna get rid of the supercharger and go with turbo next one.

 

no bubbles in the radiator....what could it be?

but also there was a cap on the overflow container that was replaced by tape and the tape came off causing some coolant to spill out. could that be the problem?

 

anyone?

 

could it be you were overheating???

 

The overflow is supposed to let water out in the event its over filling, theres a tank so if it was overfilling due to steam? It can return back to the coolent system.

I don't think its a good idea to be closing it with tape, I have no idea why the overflow would be boiling though

I had this weird issue with my fc that the overflow kept filling up, changed the oil and it stopped lol!.

 

might be overheating i didnt get a chance to get a good look.
but it looked like the temp gauge was more than halfway.
haha i just changed the oil too.

 

btw what would i do if it did overheat?

 

Need more details. How soon did it overflow after the engine was started, where was the temp gauge when this happened and what other maintenance checks have you done?

 

it was approximately 15 mins after i went for a test drive and came back. (was adjusting the timing and did some short runs up to about 6k)
i was messing around with the mixture and idle for the secondaries when the coolant started to boil.
the temperature guage was a little over halfway when i checked it.
what do you mean by maintenance checks?

 

Halfway to me is dangerous, then again this car is my baby.

 

could be a number of things..... radiator clogged, thermostat malfunction, water seal issue...... You said you didn't see any bubbles so I would check the thermostat and flush the radiator out. Do you have an e-fan or are you running the fan clutch?
Seems like there are many different water temp readings from our gauges. I know some only get to 1/4 way and some run at 1/2. My gauge never gets past 1/2 no matter how hard I run it. usually at 1/3 while cruising.

 

ahh im running 2 efans. just crossed my mind that the efans could have been off for some reason...
i havent changed the coolant yet so i guess that will be next weekends job.

 

Don't forget about the thermostat since you're going to change the coolant.
Good luck

 

The usual routine maintenance checks for the cooling system, some of which are listed above. When was the last time the hoses, belts, coolant, thermostat and water pump were checked or replaced? Are the belts hard or tightened correctly, are the hoses getting hard/dried out. If the air pump is gone, are you running a dual sheave alt pulley or a yoohoo belt, is the coolant mix at the correct 50/50 ratio, when you look under the rad cap, can you see corrosion buildup in the tubes, does the belt squeal when revving over 4k rpm, does the lower radiator hose collapse when revving, is the radiator clean so fresh air can pass through it, is the timing and fuel mix set correctly,what's the condition of the radiator cap, does it seal, does the thermostat open at the correct temperature are there 'champagne' bubbles flowing under the radiator cap once the engine is at operating temperature, is coolant leaking from the weep hole ?

These are most but not all of the checks that should be made on a 6 to 12 month basis, i.e. every other oil change. If you don't know these or haven't been doing them, then open up the FSM and start reading. Overheating is the #1 killer of rotary engines. At this point I want to be a sarcastic smart *** as all of this is basic routine 'stuff' but I'll hold my tongue and give you the benefit of doubt.

Since this started while you were the adjusting the idle and air mix screws, download and read the carb manual for your year and return them to the oem settings. Changing the timing and/or running the AFRs too lean can cause overheating.

There are other reasons that can cause your boil over, cover/eliminate the one's that I've listed so far. If the problem still persists, post back and we can go from there.
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well im running camdens supercharger pulleys and it is tight as recommended and running a holley 390 carb. seems like it likes to run at tdc, because when it was running 5-10 degrees advance it seemed like that might have been the problem. but the afr's looked ok.
the motor was rebuilt about 28k miles ago.
checked all the hoses and they are still soft and the radiator is almost brand new, but i did notice that one cap is leaking. (the one that the top radiator hose goes into the engine.) i will replace both caps and flush the coolant from the system. hopefully i can get this engine to cool down.
ill let you guys know what happens.

 

Sounds like you've lost a coolant seal, resulting in combustion gasses being forced into the cooling system. Probably doesn't happen until the thermostat opens up.

Hopefully this is not your issue...


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When you flush the system, don't forget the block drain on the driver's side. What does Camden recommend for timing advance, what psi boost are you running and is that carb big enough?

 

Said he didnt see bubbles, and would a loss of coolant/white smoke also be a symptom?

 

I think it's probably the cap being replaced with tape causing your cooling system to not hold pressure (i.e the container is open to the atmosphere, which is the ONLY way boiling can occur). Failing that I'd look at wherever the cooling system can be exposed to the atmosphere (i.e caps, hoses, etc) if you're lucky you might save yourself from a rebuild

good luck

 

I think he was talking about the plastic cap on the reservoir, so I don't think that would be a cause for this...