water pressure 190d help !

[wireman]

It will (or at least should) pressurise and this pressure should try to blow the cap out of your hands and scald you even at 80C.

I would not expect the pressure to rise to the caps blow off pressure but would expect a couple of hundred millibars at 80.

Thats why there is a warning about not taking the cap of a hot engine on the tank and in the handbook.
If you must remove the cap hot turn it only a little, sufficient to release the pressure before you turn it fully and lift it.

Perhaps you could adapt your old cap to carry a pressure guage if it is still of concern that the system is carrying to much pressure, expect 100 - 500 millibars.

Best bet is change all your hoses (at least the fat radiator ones, the parts of the heater hoses nearest the heater may be a shade awkward to access), flush the system with a good two part cleaner (active & neutraliser) follow the instructions, rinse it all out then put a stat in, refill with 40-50% antifreeze/inhibitor to finish the job properly, check it daily for one week (cold level) and if all is OK call it sorted.

Don't put anything into the coolant other than antifreeze/inhibitor anything else is just bodgeing it, replace the coolant at 2-3 year intervals.

 

[steve--o]

hi all
ok il do the hoses,stat,anti freez,i personaly think the head has a leak ,either gasket or its porus,as i think thair is two mutch pressure and certainly a lot more than it ever had.

i also dont like engine in a bottle either ,(time seved 70,s fitter apprentiship not jail :wink:)
but as a last resort i will have to go with it,try it for 30 quid,then if it doesent work,its gaurenteed recon head time .

thanks for all the input,
cheers
steve
ps is thair any of you folks out thair ,can get mi a set of merc hoses at sensible money,posted to me5 7ld kent ?

 

[television]

Do you really need the bottom hose as well, the top one is the one that takes most of the heat and pressure

 

[steve--o]

yes deffinently want to change all the lot,as we get crazey temps here july august (45 deg ) and cars just die
cheers
steve

 

[steve--o]

greeting again from a fizzin 36 deg Almeria

well,i never changed the hoses,the car carried on pressurising,i noticed a small weep from a core plug,so i removed all 4 from the exust side of the motor,ordered a 1.4 bar mecedes cap,and so far so good.

never used the engine in a bottle stuff,but fitted a new stat.

i think if i have anymore greif it will have to be open head surgery ! but so far so good !

if you ever get fed up of working in the rain,have a go at 35 deg plus sun ! ive spannerd in both,and rain wins spanners down

ta steve :lol:

 

[pomm001]

greetings from sunny almeria spain

i own a 1989 5 cylinder 2.5 deisel,i have always run it without a thermostat,as our avrage temps is 20deg or 40 deg in summer.
tha cars covered approx 225k miles and drives like new .

its been loosing water for the past week through the header tank over flow, (i think ) ive now fitted a new cap,and its seems ok ,but the cars still using water with no visable leaks
the car does not overheat or boil over and runs at approx 80 deg.

ive also removed the hoses made sure the block & rad are un blocked by running a hose pipe through them,and its all ok,ie plenty of water flowing

ive made sure thairs no air locks in the system,and if i run the engine with the header cap off and rev the motor,it dosent pressure /air bubble up (ie as it would if the head gasket had 100% blown )

my question is ,is thair anything else i have missed that will cause back pressure,or is it in with the spanners,head off,head skim and new gaskets :cry:

all advise welcome.
cheers
steve

Maybe i have missed something
why are you running without the stat ?
from memory the stat closes off the engine by pass as it opens up the rad part of the curcuit, ie take the stat out and you wil get constant bypass flow ,ie it causes overheating ! temp gauge reads low ,cylinder head cooking it knac*ers off!
i ued to work for MB doing cooling trials many years ago and Death valley in Arizona was the the ultimate cooling trial with anbients of 55 deg.
so spain should be no problem
Get it fixed and please replace the stat this time, make sure the rad is clear

 

[steve--o]

yep the new stats in and the rad is clear,its been run without a stat for at least 5 years since ive owned the car,however at the "moment "it seems ok.

just out of intrest we get july / august temps of 45 plus and we often see the new mercs "masked up" on test around our roads,i think thay test as well at the Almeria race track,along with the top bike manfs

cheers

Steve

 

[steve--o]

after changing 4 core plugs,rad cap and now the water pump its ok.

conclusion

pattern rad cap crap,now replaced with merc,4 coreplugs where rottern and blew because of the pressures.

water pump then started to weep, repaced water pump now no leaks or over pressure.

job done !

steve in 41 deg HOT!TO HOT almeria

 

[television]

after changing 4 core plugs,rad cap and now the water pump its ok.

conclusion

pattern rad cap crap,now replaced with merc,4 coreplugs where rottern and blew because of the pressures.

water pump then started to weep, repaced water pump now no leaks or over pressure.

job done !

steve in 41 deg HOT!TO HOT almeria

Nice to see that its all finished happy members make a happy forum

 

[steve--o]

thanks
i like mi old merc,and was gutted that i was going to performe open head surgery or even worst have a knacked head.

im looking for an old sl to tinker with,so no dought il be back with a long list of O,s when i do finaly manage to buy one.

cheers
steve, reporting live ! 30 mins away from the Mojacar bush fires 43 deg /melting