190 2.0lt engine heat problem/query

[brens-e200]

hi all,

well I'am back again. I have been investigating the reason for why my engine that once its heats up appears to the touch/smell to be cooking itself. The engine block gets REALLY hot ( you can burn yourself touching it { dont ask how I know

} ) as does the pipe from the water pump into the cabin. The smell of a cooking engine block can be smelt within a yard or so of the car.

The car will run a smooth as a sewing machine while warming up but once hot appears to run rough. I have had many different makes/models of cars ( saab, volvo,audi ) and this is the first time I have ever experienced such a problem.

OK here's what I've done/noticed so far on my 1990 2.0ltr

Actions:

1. coolant flushed ( and rad ) and replaced and correct ratio of water/anti-freeze used

2. coolant system has been bled many times without any change ( had front of car up on jacks )

3. thermostat replaced and verified working before installation

4. in situ thermostat works as once normal temp reached top rad hose become warm and starts to work as expected.

5. in car heating works just fine

6. expansion bottle cap replaced

7. installed capture bottle for expansion tank over flow and no leakages.

8. replaced fan-control switch

9. verified that the fan kicks in as the temperature climbs about 90c

noticed:-

1. top hose while not rock hard is stiff when pressed.

2. not loosing any coolant so that wipes of a water side head-gasket leak

wondering:-

could a head-gasket leak on the exhaust side cause the engine to heat up due to hot gases cooking the coolant . I'am planning to get a local garage to do a sniffer test next week buy was wondering is there anything i may have missed.

any idea's would be appreciated as i want to avoid engine damage so I'am currently keeping driving to a minimum.

thanks in advance

brendan

 

[grober]

Sounds like a partially blocked radiator or failed water pump [ vanes broken or detached from shaft]. Are you sure you have the right pressure cap for the coolant system. Other possible weirdness [ failure of gearbox to change into fourth! or binding brakes]-- posing extra load on engine. ---- other wise head gasket failure but that usually means a rock hard top radiator hose.

 

[brens-e200]

hi grober

thanks for the reply. I got the cap from my local dealer ( quoting the vin ). The coolant gets very hot regardless of if the car is stationary or moving ). The rad has been flushed and the output flow appears to match the input flow strength.

if its the pump how can I best test it?

regards

brendan

 

[grober]

Difficult to say to be honest. Without draining the system you could try removing the Poly V belt and rotate it by hand. Zero resistance would indicate that the vanes are gone. This is only likely to happen with a cheap replacement pump which can have plastic vanes unlike the Mercedes orginal. THIS post might help DIY video water pump removal

 

[Smartchoice]

Have you checked the head gasket?

 

[brens-e200]

hi grober

thanks for the advice on how to do a manual check of the pump and it will be my next step. If the vanes are gone does that imply they are floating around the block somewhere or just that they are loose on the spindle and not pushing water ???.

@smartchoice getting the head gasket checked for exhaust leaks will be the next step if the manual pump checks out ok.

regards

brendan

 

[johnkyte]

A simple check to see if head gasket gone or not is to
Remove filler cap,,,get water up to full temp,,then secure a condom onto water filler neck,,making sure to block water overflow
Continue to run engine---if condom continues to grow in size---then head gasket or cracked head are likely causes of your problem