99 6.5, new to this forum

[Mcolabella]

I am new to this forum.
I own a 99 Express with 242000 miles the van is a little beat up and I'm at the point well I don't want to junk it but I would like to keep it running well enough to use.
Some of the issues I am having are as follow.

1. Occasionally while running down the highway it will go into limp mode, then will run for week 2 weeks a month or two days before having the same problem
Already changed pmd

Thinking maybe it might be vacuum pump because the vents inside will not switch until I am up to speed thought maybe it might have something to do with the wastegate solenoid.

2. Hard to start which I believe is due to glow plugs and injectors injection pump was replaced at around a hundred forty thousand miles

3. The biggest concern cost-wise I believe it has a head gasket issue every since I purchased the van with a hundred thirty thousand miles the radiator light has always come on it never really overheats just always top it off when the light comes on.

I really do not mind spending some money on injectors glow plugs and a vacuum pump but do not want to dump a head gasket kind of money into it

[DmaxMaverick]

Welcome aboard!

If you're getting limp mode and/or defueling, check for DTC's (trouble codes). The SES lamp should be on, at least while it's happening. The codes should remain in history for at least a few warm-up cycles, so check for them at your soonest convenience. While it could be a vacuum pump issue, your HVAC controls are all electric. Your vacuum pump should be producing about 20" hg at idle, at the pump outlet (more is better, but 20" means it's enough to not cause issues). Original vacuum plumbing on a 20 year old rig is always suspect, as well.

Hard starts can be caused by a dozen things (some times all at once). If your Wait to Start lamp is coming on when it should, check the harness and individual glow plugs. If they show continuity and/or near a dead short (a few ohms at most), they are likely good.

Could be a head gasket or other cooling system issue. If you have no external leaks, or no other obvious indications of a coolant leak, change the pressure cap (change it anyway, they're cheap). If it continues and pursuing head gaskets isn't an option, go the a GM dealer parts counter and ask for "Cadillac Tablets" and add them to the coolant. They are coolant sealing tabs that work better than any others for minor leaks, often including head gaskets.

[Mcolabella]

Thanks for information,


Welcome aboard!

If you're getting limp mode and/or defueling, check for DTC's (trouble codes). The SES lamp should be on, at least while it's happening. The codes should remain in history for at least a few warm-up cycles, so check for them at your soonest convenience. While it could be a vacuum pump issue, your HVAC controls are all electric. Your vacuum pump should be producing about 20" hg at idle, at the pump outlet (more is better, but 20" means it's enough to not cause issues). Original vacuum plumbing on a 20 year old rig is always suspect, as well.

Hard starts can be caused by a dozen things (some times all at once). If your Wait to Start lamp is coming on when it should, check the harness and individual glow plugs. If they show continuity and/or near a dead short (a few ohms at most), they are likely good.

Could be a head gasket or other cooling system issue. If you have no external leaks, or no other obvious indications of a coolant leak, change the pressure cap (change it anyway, they're cheap). If it continues and pursuing head gaskets isn't an option, go the a GM dealer parts counter and ask for "Cadillac Tablets" and add them to the coolant. They are coolant sealing tabs that work better than any others for minor leaks, often including head gaskets.