water bubbling out

playtime · November 13, 2011, 12:36:18 AM

Sorry in advance, if this is a stupid question, but my understanding of a head gasket blown on a piston engine is, one of the usual signs is the water being pressurised and being forced out of the expansion bottle. However on my FD, which starts and runs well enough starts to bubble water out of the radiator cap at the top of the neck at the side of the engine. Any ideas on what the problem is and am I looking at the water seals gone and another rebuild? Car was bought with a full Jimmys engine rebuild less than 2k miles on it when I bought the car last year, and the car has done less than 1k in my time. It could hardly be broken already? Quickly loosing the love for rotary :2Rolleyes

philiwily · November 13, 2011, 02:01:31 AM

It might just be the cap that is faulty. When the engine is cold and the cap is off is there a lot of bubbles?
Not sure by your post if its the AST or the top neck that is leaking but just incase, the pressure cap goes on the AST and the nonpressure cap goes on the top next to the alternator.

playtime · November 13, 2011, 08:25:53 PM

Quote from: philiwily;798614It might just be the cap that is faulty. When the engine is cold and the cap is off is there a lot of bubbles?
Not sure by your post if its the AST or the top neck that is leaking but just incase, the pressure cap goes on the AST and the nonpressure cap goes on the top next to the alternator.

Thanks for the reply lad. I assume you mean the ast beside the radiator? No leaks coming from the cap on it. It is bubbling water out of the cap at the top of the neck that is right beside the alternator. Starts bubbling out water within 5 min of startup and needs a cup of water to refill by the time shes up to normal operating temp (after 10 minutes). Saying that, if I drive for a hour, the car does not run dry or need much more than the original cup. Am I correct in assuming a new 0.9 bar rad cap would fix it?

What are the classic signs of the water seals have gone? and are some bubbles normal on startup, if the neck cap is off?

Cheers in advance for any info :burnout

turbo boy · November 13, 2011, 08:50:46 PM

Is your buzzer coming on when it needs water?

playtime · November 13, 2011, 09:05:09 PM

Quote from: turbo boy;798705Is your buzzer coming on when it needs water?

no buzzer lad. Im only loosing a mug or so every time the car is started and allowed to warm up. Drove her between garages other day (20 miles, 25 min journey and she only needed mug and a bit. Not throwing steam into the engine bay or water all over the engine bay, just a wee dribble leaking around the top of the alloy neck

turbo boy · November 13, 2011, 09:16:19 PM

Thats what mine was doing buts its got alot worse now can barely drive it 25miles without "filling her up"
Check to see if your fans are coming on .

You could replace both rad and ast cap.
Fush the system out too might just be a small airlock.

playtime · November 13, 2011, 09:52:12 PM

This is where Im getting confused. If the ast cap was faulty, would there not be a leak around it, rather than a leak around the neck cap? I was thinking of fitting another ast pressurised cap onto the neck, or just remove the ast completely and swap the asp cap onto the neck. I would also assume if engine is ran without the neck cap, that would force any airlocks out? Sorry for all the questions. PS I was planning to remove the ast completely, fit a fc neck cap section, and fit a new alloy rad, with electric fans controlled by a switch

adib · November 24, 2011, 11:43:45 PM

mine keep over heating and it was the ast cap, change both off them if a fd and see what happens

playtime · November 25, 2011, 11:12:08 PM

New alloy rad going in this weekend. Just need to look into the do I remove the ast and fit a fc filler neck and have one less cap to leak or keep it all as original dilemma........

RobMatthews · November 26, 2011, 09:46:42 AM

How exactly are you checking this problem?-As you may just be causing it yourself...

The system works under pressure, at a certain pressure (after the car warms up)water is pushed from the ast to tank in front of the o/s wheel, If you warm the car up or after a drive dont give the system enough time to cool right down and suck the water back from the tank befor opening up either the fill cap beside the alt or the ast cap you are depressurising the system meaning it \'looks\' like your loosing water....

If you decide you want to go the route of fc filler neck, give me a pm i have the bits you need-including a new pressure cap

playtime · November 26, 2011, 07:11:04 PM

Cheers lads.
@rob. No Im not removing the caps. I start the car, and after couple of minutes as the temp is rising to normal before I drive off, water starts leaking out around the filler neck cap. There are no other leaks visible. I take for a drive and then leave for at least 24 hours to let system cool down. I then open the filler cap, and she needs at least a mug of water to bring back up to level. Im wondering if the pipework from the ast to the overflow tank in front of the driver wheel, was blocked, would it force water out the filler cap, once pressure has built up, and cheers for the offer of the fc filler neck. I need to look into the pros and cons of each type fd or fc before I decide either way.