too much pressure

[porha]

hello,we have a boxster 2.5 98,we bought it from US,little damadged and now repaired.Actually my cousin drives the car.When we did the car,we put on a new radiators,half of hoses,used coolant tank,new cap and bleed the system properly with new coolant.The car worked fine for 3000km until the venting hose from oil cooler to tank cracked,and he :clapping: drove the car for another 1 hour with coolant on min or less and temp.light flashing.He said the temp.never raised above 8 of 180 or less on the cluster and light was flasing all the time and was not staying on. :clapping:

So I changed the hose and bleed the system properly(did it many times),and changed new cap.And the system circulate from 102,103 to 97deegres cel. on PST2,seems fine.You can drive the car for hours with normal driving(up to 5000rpm max) and everything is fine, but when you go on highway or open road and rev the car up to 6000rpm for a few times,the coolant leaks from the cap.Seems like too much pressure,and bad head gasket.again it was bleeded properly and new water pump was added.No coolant oil mix,no smoke,no temp.raising,normalpower.Bad head gasket at exhaust and coolant mix,or is there any other possibilites.Help would be :welcome: ...thank you luka

[Wayne R. Dempsey]

At first glance, I would guess you have too much coolant in there. I would empty it out a bit and then try my bleeding procedures here: http://www.pelicanparts.com/techarticles/Boxster_Tech/29-WATER-Flush/29-WATER-Flush.htm

Let us know how it turns out!

-Wayne

[Wayne R. Dempsey]

There's also a coolant overflow hose too, has there been any leaking out of that?

-Wayne

[porha]

There's also a coolant overflow hose too, has there been any leaking out of that?

-Wayne

Hi,I have bleed the car once by your procedure and there is no differences,there is leaking by the right rear wheel but it was leaking from overflow hose from top of the tank,after it leaks I hear pressure coming out from the tank cap and the trunk is dry,and there is still enough coolant -on min or little above the mark on tank.I tryed with other venting clip valve,no differences.Is it possible there is something cracked inside the tank?

sorry for my english

thanks

[porha]

Hi

I still didn't get the parts(2 hoses),than I'll bleed the system again,I will post for results.

I tryed everything what I found here on forum,also I red the article from you(Wayne),I checked the plugs(they are all the same colour),no misfires with 400km,oxygen sensors are good tested with PST2,tailpipe no marks for coolant burning-I think,

Is there some other ways to analize bad head gasket in my case,before tearing the engine apart or without pressure test at porsche dealer.There is no oil coolant mixing,but there is pressure in cooling system at high rpm on road.before that driving with broken vent tube,the cooling system worked perfectly, so probably it is head gasket.

any ideas would be really help for me

sorry for my english

thanks

[sasha055]

Please excuse my stupid questions.. but How a head gasket can lead to increase in coolant pressure?

The only thing that should happen is coolant mixing with oil and possibly.. less pressure in coolant..

Thanks

Sasha

[grover]

Please excuse my stupid questions.. but How a head gasket can lead to increase in coolant pressure?

The only thing that should happen is coolant mixing with oil and possibly.. less pressure in coolant..

Thanks

Sasha

If the gasket fails between a cylinder and coolant chamber, it will draw coolant into the cylinder during the intake stroke, and blow hot gases into the coolant system during compression and power strokes. Symptoms are loss of coolant with no drips, and increase in coolant system pressure.

[moot4000@aol.com]

Hi, Here in the UK our AA breakdown guys carry a piece of kit that can check Head Gasket leaks, ie Head Gasket leaking into water system, causing over pressuring, or constant water loss with no visual leaks, and no engine misfiring, The kit uses a special blue liquid that is put into a glass tube, it has a rubber sqeezie bulb on one end, the other end has a rubber seal with a one way valve in it, You run the engine till its warm with the radiator, header tank cap off, then the sealed end of the glass tube is inserted into the Rad/Header tank, The Rubber Bulb end is sqeezed a few times to draw air into and through the glass tube with the Blue Fluid in it, if any exhaust gases are present, The blue liquid will turn Green, meaning Head Gasket or Cylinder Head Problem, over here in the UK, we call it a Sniffer test, I'm sure it must be available in the USA, I've used this piece of kit many times when I worked for the AA, saves a lot of time hassle, and to prove to sceptical car owners that it works, just use it near a running exhaust and the colour change is instant, good luck.

[porha]

Hi, Here in the UK our AA breakdown guys carry a piece of kit that can check Head Gasket leaks, ie Head Gasket leaking into water system, causing over pressuring, or constant water loss with no visual leaks, and no engine misfiring, The kit uses a special blue liquid that is put into a glass tube, it has a rubber sqeezie bulb on one end, the other end has a rubber seal with a one way valve in it, You run the engine till its warm with the radiator, header tank cap off, then the sealed end of the glass tube is inserted into the Rad/Header tank, The Rubber Bulb end is sqeezed a few times to draw air into and through the glass tube with the Blue Fluid in it, if any exhaust gases are present, The blue liquid will turn Green, meaning Head Gasket or Cylinder Head Problem, over here in the UK, we call it a Sniffer test, I'm sure it must be available in the USA, I've used this piece of kit many times when I worked for the AA, saves a lot of time hassle, and to prove to sceptical car owners that it works, just use it near a running exhaust and the colour change is instant, good luck.

Hi, thanks for info on sniff test,I just found one, will order it.In our country this thing is TOP SECRET :) unless you know what are youlooking for.

thanks again

[porha]

At first glance, I would guess you have too much coolant in there. I would empty it out a bit and then try my bleeding procedures here: http://www.pelicanparts.com/techarticles/Boxster_Tech/29-WATER-Flush/29-WATER-Flush.htm

Let us know how it turns out!

-Wayne

Hi, I tryed it again,but no differences.I drained the system,but didn't loose the hoses on radiator and forgot to open valves from heater.And I got 17liters of coolant in the system,so I think it is bleeded.The system capacity is 19,5 lit.,I think.The car has now new pump(was noisy),new tank and cap,half of hoses(were worn),thermostat,new radiators from begining(when we imported the car from US and repaired it),by the way-its like new.

I did it like you said in your article,but I don't understand opening the cap when the temp. is above 70-75 deegres cel. In my case can't be opened,because there is too much of coolant loss.I did the bleeding up to 75deg.cel.,and than I left the cap closed.You can not force the airlocks to go out by that way(opening the cap)like wiht some other cars,not with boxster.Left the car with revs to operating temp.with heating on,valve open,everything is working fine.The circulating is good (102 deg.cel.when vents go on and drops to 97).I wait for few cycles and turned off,the level was fine in the tank.Next day I saw that level droped for few centimeters and when I opened the cap a few more-to MIN mark.I add 1 liter so,first day 16lit.and second day 1lit.Closed the bleed valve and went for few rides and everything is working fine.With no smoke,or misfire and coolant loss,normal temp.on guage.I drived normaly with some revs to 5000rpm.

After 2 day when I opened the cap there was still pressure in tank,thats not normal.I will see what happens tommorow when I'll go for a ride.I still didn't get the snif test,but I will take the engine out and do the headers job and everything else with our friend mechanic-worked in factory on engines.And will check the spark plugs again tommorow.I'm 100% sure that the gaskets are bad.

I will report when the job is done for results,some time is needed because of work with other cars.

thanks again

sorry for my language