Marchanic
27-02-2023, 11:03 AM
(Problem solved: Blocked heater matrix / heat exchanger - replaced with a new one)
Hello everyone!
I am trying to help a friend and his missus with their overheating Golf mk6 2010 1.6 TDI Diesel CAYC Hatchback.
The symptoms are very weak interior heating (worst at passenger side), as well as overheating engine under load (uphill) at high gears (low rpms). While the engine coolant temp rises to 110 degrees celsius, the interior heater is blowing cold air. As long as the RPM's are around 2k it seems to be able to keep the temperature around 90 degrees celsius, maybe abit higher.
The car has been like this for maybe a year. So it's seen alot of a 100+ celsius temps during the last year.
It felt like the return hose on the heater matrix was not as warm as the inlet hose on the heater matrix.
Tested coolant flow at the coolant expansion tank return hose, seemed fine and increased with RPMs. Flow compared to my 2008 Skoda Octavia BMM engine. Color of the coolant was closer to clear/yellow than red. Coolant level around 1-2 cm below minimum before removing the cap.
Car has dome 134 000 km / 83k miles. No sign of a timing belt / water pump replacement in the service history book. The change interval stated in the service manual is 210 000 kms.
No obvious related fault codes in VCDS.
Test drive with VCDS hooked up, monitoring engine coolant temp, oil temperature, coolant temp at radiator outlet, radiator fan
Ambient temp while troubleshooting: 4 degrees celsius
Engine coolant temp as high as 115 degrees celsius (needle in dash went above 90 when VCDS showed 110 and up)
Oil temp follows coolant
Coolant temp at radiator outlet: between 13-25 degrees celsius. Radiator hoses cool to the touch.
Radiator fan as high as 90% engaged when the coolant temp was highest
My first thought is obviously a faulty thermostat because the radiator isnt getting any action, and a blocked heater matrix.
I have seen some forum posts on the CAYC engine where replacing the thermostat ain't helping, but bypassing/changing the heater matrix has helped. Could the coolant flow be disturbed resulting in thermostat not opening because of a blocked heater matrix?
Attached is the VCDS auto scan and production data sticker, as well as a picture of the coolant return flow to expansion tank at 2000 engine RPM.
Grateful for any comments or advice. Thanks.
3892738926
38925
Hello everyone!
I am trying to help a friend and his missus with their overheating Golf mk6 2010 1.6 TDI Diesel CAYC Hatchback.
The symptoms are very weak interior heating (worst at passenger side), as well as overheating engine under load (uphill) at high gears (low rpms). While the engine coolant temp rises to 110 degrees celsius, the interior heater is blowing cold air. As long as the RPM's are around 2k it seems to be able to keep the temperature around 90 degrees celsius, maybe abit higher.
The car has been like this for maybe a year. So it's seen alot of a 100+ celsius temps during the last year.
It felt like the return hose on the heater matrix was not as warm as the inlet hose on the heater matrix.
Tested coolant flow at the coolant expansion tank return hose, seemed fine and increased with RPMs. Flow compared to my 2008 Skoda Octavia BMM engine. Color of the coolant was closer to clear/yellow than red. Coolant level around 1-2 cm below minimum before removing the cap.
Car has dome 134 000 km / 83k miles. No sign of a timing belt / water pump replacement in the service history book. The change interval stated in the service manual is 210 000 kms.
No obvious related fault codes in VCDS.
Test drive with VCDS hooked up, monitoring engine coolant temp, oil temperature, coolant temp at radiator outlet, radiator fan
Ambient temp while troubleshooting: 4 degrees celsius
Engine coolant temp as high as 115 degrees celsius (needle in dash went above 90 when VCDS showed 110 and up)
Oil temp follows coolant
Coolant temp at radiator outlet: between 13-25 degrees celsius. Radiator hoses cool to the touch.
Radiator fan as high as 90% engaged when the coolant temp was highest
My first thought is obviously a faulty thermostat because the radiator isnt getting any action, and a blocked heater matrix.
I have seen some forum posts on the CAYC engine where replacing the thermostat ain't helping, but bypassing/changing the heater matrix has helped. Could the coolant flow be disturbed resulting in thermostat not opening because of a blocked heater matrix?
Attached is the VCDS auto scan and production data sticker, as well as a picture of the coolant return flow to expansion tank at 2000 engine RPM.
Grateful for any comments or advice. Thanks.
3892738926
38925