Bad motor or something else?

[adam g]

I am working on a customers van. The customer owns a construction company. His help against all warnings still used either on it. This thing is hard starting even hot. When started blows white smoke,and misses under a load. Sounds terrible. I put my lisle hydrocarbon/head gasket tester in the radiator. It passed. I took compression through the glow plug holes. 7 cyl in the 400 to 425psi range. One hole wouldn't quite make 350. Is that enough to cause a dead hole or do I have a bad injector that has washed down that cyl. Customer complained of having to add a quart of oil every 500 miles but for a 200,000 mile motor I thought that was bearable. Oil was right at full didn't appear to be contaiminated with fuel or antifreze. What do you thinK?

 

[LCAM-01XA]

Adam, hard staring when hot is a typical symptom of the injection pump failing - an easy trick to verify that is with the engine nice and hot to slowly pour lukewarm water on the end of the injection pump where the pressure lines connect to, be careful to not get any water on the front end oft he pump where it bolts to the gear housing tho, as that may cause the input shaft to snap. What this procedure does is cooling the head of the pump, as when pump is worn the expansion it sees during to heat soak from the engine is enough to make it lose tolerances in the head and not build up good pressure to fire the injectors. At least that's my understanding of it.

On the weak compression of one cylinder - no, I do not think that will not cause a no-start or hard-start condition when hot, as last weekend the #5 injector loosened up on me and caused a compression leak on that cylinder - never had issues starting truck tho, it would fire up almost instantly whether it was cold or hot.

 

[GenLightening]

Pull the injectors and see how many are wet, especially the one with low compression. Mine was doing the same and I found 5 bad ones.

 

[towcat]

injectors are weak and pump is not long for this world.

 

[adam g]

I got done with the compression test and put it back together. It started and ran great. I pressured the radiator up left for lunch and fired it up when I came back. It puffed white smoke missed and carried on. So I am looking at heads. If we decide to rebuild this one I'll check the injectors. I guess I can't trust an automotive hc tester on a diesel.

 

[Diesel JD]

I think that you do not have head gasket problems. That white smoke could be from a bad injector or 2 That compression is within specs, but it could be better.

 

[LCAM-01XA]

JD is right, unburn fuel can be white in color.

 

[Diesel JD]

If it was head gaskets or block cavitation or similar that smoke will have a sickening sweet antifreeze type odor.

 

[adam g]

Guys why does it miss only when the radiator is pressure up? If I take the cap off the miss will clear up. If I put my pressure checker at 13 lbs the miss and smoke come back.

 

[sassyrel]

did the owner say it had been using antifreeze???? normally if a head gskt is bad--the pressure will just keep building up in the rad--and will eventually blow hoses--or the rad---you need to put the tester on that keeps track of the pressure in the rad--and if it keeps climbing---gskt--

 

[icanfixall]

Best idea is warm it up. Remove all the glow plugs and pressure up the radiater. Watch the pressure and maintain it at 13 or so lbs. Wait 10 minutes and slowly crank the motor in small bumps. Coolant will squirt out of one of the glow plug holes. Don't start the motor. That may bend a rod because of the fluid in the cylinder. Pull the injection pump fuel shut off wire so it wont start. That will tel you which cylinder is bad....

 

[adam g]

The owner doesen't know of the antifreze consumption. His help is a group of flunkees that tear everything up and try to hide it from him. But judging by the looks of the coolant being mostly water I'ld say they've been adding.

 

[seawalkersee]

Also, you may have a problem with the bolts. Though they may not be broken, it may be lifting the head in said low pressure cyl. I would be willing to bet there are at least two problems. If you are not geeting exhaust in the coolant though, it does not sound bad. But stranger things have happened. I would start with an injector and pump test but the low compression/miss could definately be a problem with the missing and white smoke. I am not a diesel specialist by any means, but as far as an engine goes, this is the same thing a gas engine could/would do (and I am REALLY good at diagnosing those).

Chris