DCBD
Senior Member
Yesterday while moving from A to B I noticed that my engine would not reach my normal cruising RPM of 2700. I understand that my engine (Volvo TAMD30) is capable of reaching 3500+ RPM but I have never had it above 2900. I was able to reach 2600 so almost there but not quite. Since I had just been crawling around the engine making checks I thought I must have bumped or stepped on something and decided to continue my travels and check it out when we settled in for the night.
After about 30 minutes I noticed that the engine temperature had settled at a higher than normal position on the temperature gauge. We continued on. After about 1 hour the temperature started to climb and it began a cycle of up and down never exceeding 200 deg but definitely trending up. This continued like this for maybe the next hour. Suddenly the temperature shot up above 200 deg. This has really got my attention now, I was thinking maybe my raw water impellor might be shot so I asked my wife to have a look at the exhaust to see how much or if any water was coming out of the exhaust exit point, she came back and told me both the water and smoke was black. I had not noticed any smoke coming from the exhaust, black or otherwise from my position at the helm.
I throttled back to 2250 and noticed an immediate response on the temperature gauge, my wife also noticed that the exhaust cleared up right away as well. We continued on course like this and the engine temperature settled in at its normal position and never moved for the remainder of our transit.
I’m not much of a hands on mechanic but I have a good understanding of how things work, so in my mind the inability to reach normal RPM and the black exhaust is telling me that I’m not getting a proper air/fuel ratio. Specifically, not enough air. This morning I’m going to check out the intake to make sure it’s clear but I’m afraid that it’s actually the turbo that is the problem. One thing I don’t understand is the raise in engine temperature, is this a normal condition when a turbo fails or am I totally wrong with my diagnosis. If I find the turbo to be stiff or stuck has anyone had any success in freeing them up. What else should I be looking for.
After about 30 minutes I noticed that the engine temperature had settled at a higher than normal position on the temperature gauge. We continued on. After about 1 hour the temperature started to climb and it began a cycle of up and down never exceeding 200 deg but definitely trending up. This continued like this for maybe the next hour. Suddenly the temperature shot up above 200 deg. This has really got my attention now, I was thinking maybe my raw water impellor might be shot so I asked my wife to have a look at the exhaust to see how much or if any water was coming out of the exhaust exit point, she came back and told me both the water and smoke was black. I had not noticed any smoke coming from the exhaust, black or otherwise from my position at the helm.
I throttled back to 2250 and noticed an immediate response on the temperature gauge, my wife also noticed that the exhaust cleared up right away as well. We continued on course like this and the engine temperature settled in at its normal position and never moved for the remainder of our transit.
I’m not much of a hands on mechanic but I have a good understanding of how things work, so in my mind the inability to reach normal RPM and the black exhaust is telling me that I’m not getting a proper air/fuel ratio. Specifically, not enough air. This morning I’m going to check out the intake to make sure it’s clear but I’m afraid that it’s actually the turbo that is the problem. One thing I don’t understand is the raise in engine temperature, is this a normal condition when a turbo fails or am I totally wrong with my diagnosis. If I find the turbo to be stiff or stuck has anyone had any success in freeing them up. What else should I be looking for.
