Left Exhaust Manifold TS 95

Hi guys,

Today I had some problems with my TS95 3.8.
I noticed the oil pressure indication had dropped, touching the red band when idle.
Being an engineer myself I got worried and pulled over to check the oil level and a gvc. (Gvc= general visual check :))
All looked ok but when I drove on I noticed a lack of power when accelerating. Only at midrange because when I floored it, most umphfh came back.
Also the coolant temp was higher than normal, just reaching the 100.
During the inspection at home I found the heatshield of the forward (lh) exhaust manifold had dropped (rotted) off and got stuck between the fanhousing and some tubing. The fan was not blocked and was fully serviceable.
Also clear was a crack in the exhaust manifold at the #6 cilinder downpipe.
I removed the heatshield and tried another run.
It was cooled down and the oilpressure was back normal. Also the power. Me happy :smooch:.
But after some time, say 15 minutes in traffic, all shit was back. (Low oil pressure, hotter coolant, lack of power) My not happy :runaround:
My questions are:
Can the crack cause the lack of power in midrange or can this be caused by the overheated engine oil?
Can the crack and inevitable outlet of hot gasses somehow cause the engine oil to heat to the point it looses oil pressure? (I think the hotter oil will also heat up the coolant) or is there another cause for this heating oil.
How is the general experience with changing the manifold? (Bolts and nuts look quite reacheable but off course rusted) Seized nuts will not make me happy if I look at the available space.
I found the manifolds still available for around $150,-.
If it solves these problems I will give it a shot.

Thanks for coming back with your experience on this.

Andy

The exhaust manifold often get cracked in that position. But the problem is not that exhaust gases is leaking out, it is more that air is sucked in and mixed with the exhaust gases. The oxygen sensor them thinks that the engine is running lean and gives the signal for more fuel to the engine. The result is that the engine will run rich, and the unburnt fuel will be burn in the cat along with the air sucked into the crack. The engine will run cooler than normal because of the extra fuel cools it. The cat will be hotter than normal.

You may want to fix the crack by welding or replacing the entire manifold, but I do not think the other problem you are reporting is due to the crack.

Have you checked the coolant and oil levels?

Thanks for the feedback.
I have checked the levels of oil and coolant.
And I agree the leaking manifold is not likely to be the cause.
Done another run today with the windows down and I noticed the engine sounding a bit harsh, mechanicly.
So the next suspect is a worn waterpump.
Any issues known on that part?

Hava a nice day.

Andy

There are no issues on the water pump as far as I know. I have never heard of loosen pump wheels, just leaking water pumps. I did replace my water pump this winter at about 250 000 km. I think I did replaced the original pump. It is a very simple and straightforward job, as long as you do not break any of the screws. Replace the serpentine belt as well, if needed.

I can see you are in Holland. Where do you get parts from? Do you have any tip on web shops in Europe?

Hi Nicke,

I order the parts mostly straith from the USA. (On-line stores or Ebay automotive)
Prices are much more friendly there and sending parts never has been a problem yet.
If parts are needed fast then I use C&P carparts in Holland.
Good store and fair prices.
http://www.cpusaparts.nl/
How are prices and availability in Sweden?

But back on topic, the pump is so straight forward it either works or is shot completely.
A blown head gasket would give additional signs, like white oil or creamy coolant. Non is noticed.
The search goes on...
Any ideas are welcome of course.

Have a nice day,

Andy

Just out of curiosity, have you connected a scanner to your car? Is there any chance it's running lean?

Just checked the codes, no codes stored. Also did a monitoring run, all values look normal and no weak cilinder detected.
Will take it for a good testrun soon and hook up the code reader again.