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Cooling system issues

1079 Views 21 Replies 2 Participants Last post by  rwfnetworking
2003 NBC 2.0l has been running hot and causes high temp CEL. Suspected water pump since return flow to reservoir was non existent and would produce bubbles in reservoir if blown into. Pulled water pump, it looked ok. Also Pulled and tested the thermostat and it was ok.

Is there any other blockages that I should check for?

Heater core gas been bypassed before I bought this.
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What temps are you seeing, are you seeing any specific light modes in the speedo cluster come on and/or monitoring the temps using a scan tool; then used a infrared temp gun to confirm this or see, any visual aspects of overheating like boiling coolant in the coolant tank or overflowing coolant, cooling fans on constant max high speed, etc?

Here are the coolant light modes:

Blue coolant light = engine cold
Flashing blue coolant light = fault in the coolant monitoring system
Flashing red coolant light = low on coolant
Steady red coolant light = engine overheating, pull over and stop engine IMMEDIATELY and do not run until the problem has been identified.

On the trouble code side of things; please post any codes, you are getting.

Here some videos; going over overheating issues and things to check, by exovcds on youtube:

More videos of his to review; from more checks to refilling the coolant.

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Classic VW cooling system failures; that can make diagnosis confusing:

If you see bubbles in the coolant tank and suspect a head gasket failure; you might try a combustion leak test of the cooling system and/or a compression, leak down test.

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Based, upon the temp monitoring results; technically, those are in the normal range. The code, seems to point to; a possible defective coolant temp sensor?

Review the videos; return coolant, into the tank, would be normal cooling system operation. We have seen cooling systems; that were contaminated, with incorrect mixed green, vw pink g12/13 coolant, which developed into a nasty, thick coagulated mess, that plugged up various hoses and passages.

You might pull the cooling tank return hose; try to blow through it. I had one that was clogged; many have a plastic flow restricter with a tiny coolant passage. In that case, i took a small stiff wire; pushed though the blocked passage, cleared the obstruction, flushed out the hose, blew out with compressed air and confirmed free flow with water. I reinstalled and the coolant flow was restored.

In the case of the contaminated vw Jetta withba 2.0L i worked on; the coagulated junk tended to rise to the higher hoses, passages and coolant tank. I had to remove, a bunch of hoses and use wires, to push out blockages and pipe cleaners to scrub everything out with dawn dishwashing soap and finish off by flushing the whole cooling system, until the water was clear, gunk was mostly gone.

Normally the hoses should have been replaced but the customer was tight on cash and we did the best we could by cleaning and flushing the whole system and it ended up working fine, cooled in normal ranges, didn’t over heat.

However, not being the ideal repair; some residual tiny bits of junk remained floating around, even after 3 flush cycles but didn’t seem to affect cooling system operation.

You may need to remove a bunch of hoses and confirm; free flow from the many areas of the cooling system, clean them out, blow out with compressed air and flush the system throughly, until water runs clearly.

Then, refill the system with coolant and ideally; use a vacuum fill tool and see if things flow, as they should and review the exocvds videos to follow overheating checks, to confirm flow and operation is normal.

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So, has the water pump, coolant temp sensor and/or the thermostat been replaced? Ok, report back your results and we can go from there.

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So, did you get the overheating issue and/or the coolant temp sensor, replaced?

As to the injector and previously mentioned cooling related problem; are there any trouble codes or have you cleared them, see what comes back?
Ok, I think we discussed this before; what troubleshooting, testing or repairs have you performed, on this issue? Any parts replaced?

Also, as always, post the trouble codes and not just the descriptions. Thanks.

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Since, you are using OBDEleven; you might review this video and use it, to read live data, the misfire counter as the engine is running.

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So, i guess you need to revisit the misfiring issue; what testing, troubleshooting, repairs have been done and/or new parts, have been installed?

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Any updates to the misfire issues? Does, it seem; like you have the issue licked? :)
Finally, glad you that handled; good work! :)

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