high pressure

schakal · Post by **schakal** » Wed Feb 01, 2006 9:44 pm

i have a renault 19 with the 16v engine that produces 137bhp of power standard (probably a few horses down now after 14 years)

anyway ,there is some extreme pressure in the cooling sytem somehow . split 4 different pipes and a brand new heater matrix in the last 3 months and this is getting a bit annoying now.
suspected of head gasket failure and done a compression and the result is as follows

i have been told this results are prety good for a 127k engine but however the problem is still there .
i filledthe sytem yesterday and drove the car about 20miles and parked up ,opened the bonnet to see the coolant is pissing from the top radiator hose where it connects the thermostat housing . took the hose out and swapped with a spare one . took for a spin( 4-5 miles) parked up again and saw the water level is gone down and the water hoses are solid as in very high pressure is built in them .

any ideas what might be causing this guys ???

cylinder leaking in to the water channels may be ???

Guest · Post by **Guest** » Thu Feb 02, 2006 12:10 am

those results are enough to show they are all similar and compression is good.

4 different pipes or 4 x the same pipe?
do you have mayo in the oil?
do you have a blockage in the pipe runs?
do all the pipes get hot?
is the pump doing its job?
does the thermostat work?
is the auxillary pump working?
has the system and rad been bled up?

haz

schakal · Post by **schakal** » Thu Feb 02, 2006 10:17 am

4 different pipes or 4 x the same pipe? DIFFERENT PIPES ALL AROUND THE CYLINDER HEAD AREA

do you have mayo in the oil? NO

do you have a blockage in the pipe runs? NOT SURE NOW

do all the pipes get hot? WILL CHECK THAT

is the pump doing its job? MUST BE,AS THE TOP PIPE IN TO THE WATER
TANK BRINGS IN WATER FROM THE HEAD

does the thermostat work? YES I TOOK IT OUT AND DONE THE HOT WATER IN A PAN TEST

is the auxillary pump working? SOUNDS LIKE WORKING ,THEY GO FOR 8 MINS AFTER ENGINE SHUT DOWN

has the system and rad been bled up? NOW ,NOT SURE HOW TO DO THAT TO BE HONEST ,CAUSE THE COOLING SYSTEM IN THESE CARS IS A MAZE AND AIR LOCKS ARE ALWAYS HARD TO AVOID ,I LET THE RAD. BLEED SCREW OPEN WHILE FILLING THE SYSTEM AND SHUT IT AS THE COOLANT URGED . ALSO THE HEATER WORKS LIKE A FINNISH SAUNA ,ITS VERY HOT !!!!

DO YOU KNOW A DIFFERENT WAY ???

haz@nocturnal_development · Post by **haz@nocturnal_development** » Thu Feb 02, 2006 12:27 pm

a little trick is to lift the tank out of the engine bay, not loads, just so its higher than the rest of the system (pipes still connected of course). this will help alot of the air find its way to the tank. there are places in the system, such as the rad, that has bleed screws which, like you mentioned, you open while filling the system. i also over fill the coolant a bit then repeat the bleed process while the engine is running just to double check.

you could have a blockage (i know its not your matrix, but sometimes these can become blocked with corrosion/gunk. they may not be completely blocked but the pressurized coolant will take the easiest route and around the blockage wont circulate, and overheat.)
are you losing water?
do you have a split pipe somewhere as this could be letting the air in which is causing the problems?

haz

schakal · Post by **schakal** » Thu Feb 02, 2006 1:03 pm

haz@nocturnal_development wrote:a little trick is to lift the tank out of the engine bay, not loads, just so its higher than the rest of the system (pipes still connected of course). this will help alot of the air find its way to the tank. there are places in the system, such as the rad, that has bleed screws which, like you mentioned, you open while filling the system. i also over fill the coolant a bit then repeat the bleed process while the engine is running just to double check.

you could have a blockage (i know its not your matrix, but sometimes these can become blocked with corrosion/gunk. they may not be completely blocked but the pressurized coolant will take the easiest route and around the blockage wont circulate, and overheat.)
are you losing water?
do you have a split pipe somewhere as this could be letting the air in which is causing the problems?

haz

just done another gentle run for 4-5 miles ,she is heating pretty fast and a fair bit of smoke coming of the back pipe when i rev up to 3k in neutral but while the car is running under load ,the smoke disappears .

after that run i lost a bit of water in tank ,pipes are solid again under pressure and as i slowly unscrew the pressure cap water level raises .

also touching the top rad hose where it connects to the thermostat housing under the jubilee clip is wet from coolant hence your theory sounds right ,sucking air from that hose if the water is getting out .
but this is the second time since yesterday now ,
this is silly though i checked the thermostat and it does work (brand new one from halfords) anyway if the thermostat was stuck shut the water would not be getting through the top rad hose and cause the pressure in the hoses .

on the other hand when i killed the engine i checked the radiator ,top and bottom of the rad is hot as well

even though i flushed the sytem properly a few months a go i will do it again to see if i can free and possible blockages

stu chacks · Post by **stu chacks** » Thu Feb 02, 2006 1:04 pm

Cooling system filler cap?

Stu.

schakal · Post by **schakal** » Thu Feb 02, 2006 1:07 pm

stu chacks wrote:
Cooling system filler cap?

Stu.

its a brand new one from renault dealer i bought yesterday

stu chacks · Post by **stu chacks** » Thu Feb 02, 2006 1:31 pm

I always look for the obvious 1st! That was prob I had with one of the MG's after much searching.

Tried running it with the cap off all together?

I'd go for high pressure flush, disconnect both ends of cooling system and hose it out. Thought: You haven't put the thermostat in upside down? Seen that happen before.

Stu.

JohnTurbo · Post by **JohnTurbo** » Thu Feb 02, 2006 1:37 pm

Sounds a lot like a gasket. I blew my rover's head gasket, and it pressurised the water system pretty much like you explain. It also blew two pipes.

Only a small leak required over the gasket to cause issues.

Mark 480s · Post by **Mark 480s** » Thu Feb 02, 2006 2:06 pm

Hi schakal
It sounds like the head gasket has blown. My volvo 940 did this, the gasket went between one of the cylinders and a waterway. So you never get any oil in the water or water in the oil. mine split two oil water cooler pipes under the car. a pig to replace!
the easy way to prove this is when the engine is cold start it and unscrew the rad header filler cap you will see bubbles coming up thru the water. you can also get some test tablets you add to the water that changes colour if there is CO disolved in the water.
I also compression tested the engine and all the readings were fine!

regards

Mark

schakal · Post by **schakal** » Thu Feb 02, 2006 3:49 pm

sounds like you all are right ,
i just was thinking wishfull as possible

i have also found a strong smell of petrol in water tank today
that explains it all clearly . hopefully its the headgasket only but not a cracked block/bottom end ,i got a head gasket set with brand new head bolts
,a wise investment i have done a few months ago
i want to change the timing belt and the tensioners as well while i am there

and guess what ? ????? i have never done this before

gonna be fun me thinks

Guest · Post by **Guest** » Mon Feb 06, 2006 2:19 am

The heads on these renaults are renound for becoming porus (spelling?) have seen them seep water into the plug wells too, my advice would be to have it pressure tested while its off.

steve

__________________________________________
Renault 5 Monaco, with a turbine type thing that blows air in.

schakal · Post by **schakal** » Mon Feb 06, 2006 2:29 am

Anonymous wrote:The heads on these renaults are renound for becoming porus (spelling?) have seen them seep water into the plug wells too, my advice would be to have it pressure tested while its off.

steve

__________________________________________
Renault 5 Monaco, with a turbine type thing that blows air in.

the water in plug wells is a problem to do with the bonnet vent but mine has a rain catcher and i dont suffer that problem.

why test it when the head is off???

haz@nocturnal_development · Post by **haz@nocturnal_development** » Mon Feb 06, 2006 10:19 pm

schakal wrote:
Anonymous wrote:The heads on these renaults are renound for becoming porus (spelling?) have seen them seep water into the plug wells too, my advice would be to have it pressure tested while its off.

steve

__________________________________________
Renault 5 Monaco, with a turbine type thing that blows air in.
the water in plug wells is a problem to do with the bonnet vent but mine has a rain catcher and i dont suffer that problem.

why test it when the head is off???

its to test if the head has any cracks or leaks in the ports, waterways etc. its a different test to checking compression which is chambers only.

haz

schakal · Post by **schakal** » Mon Feb 06, 2006 11:46 pm

ayee ,you mean checking it for tiny cracks etc.
i have called a few places to get some prices for the job
not too bad actually

--cleaning reseating valves ,cleaning head ,new stem seals 50quid
-- pressure testing 30 quid
-- skimming the head 25quid

thats all i need i reckon before the head goes
back on (its ot even off yet though)

i also want to check the bottom end for cracks and want to do a bit of cleaning on that area as i will have some extra space to work on while the head is off .

will have a look at the condition of the tensioners and replace them if necessary .
haz , can you think of anything else that could be done while the head is off ???

haz@nocturnal_development · Post by **haz@nocturnal_development** » Tue Feb 07, 2006 9:15 am

argggh skimming !!!

most places offer skimmin but forget to mention that this alters compression and the customer may benifit from using a non std gasket, ie thicker one. higher compression will make the engine feel quicker, but will lower the det threshold. higher compression may be better for you so stick to a std gasket.

if there's no probs with the water system, and no probs with the head, then the fault could be with the bottom end. dont put it back together til you've found a reasonable cause for the overheating.

have you not considered a 16v or turbo conversion?

haz

schakal · Post by **schakal** » Tue Feb 07, 2006 1:52 pm

i dont know why i would need skimming
anyway unless the head is warped or something ??
is that right ?