Engine overheating but radiator is cold

Post Reply
Tswerie
Enlisted
Posts: 42
Registered for: 6 years 3 months

Engine overheating but radiator is cold

Post by Tswerie »

Good day

My vehicle overheats, both radiator hoses top and bottom are hot but radiator is cold and the radiator fan doesn't come on.

The heater in the car doesn't give off heat.

The following were replaced, waterpump, thermostat, fan switch and heat switch.
I've also had two pipe burst close to the water pump.

In one of the burst pipes some oil was found.

There was rust on the heat switch

Any ideas?

Sent from my MAR-LX1M using Tapatalk



Last edited by Tswerie on Wed Mar 24, 2021 8:05 am, edited 2 times in total.
User avatar
amstel18
Lieutenant-Colonel
Posts: 4834
Registered for: 16 years 3 months
Car Make: VW
Car Model: Tiguan Allspace
Membership No: missing
Location: Brackenfell, Cape Town

Re: Engine overheating but radiator is cold

Post by amstel18 »

Sounds like a blocked radiator.

rust points to lack of anti-freeze being used.
Current:
2022 GWM P-Series LT 4x4
Ex:
2018 VW Tiguan Allspace
2013 Audi A3 Sportback 1.8 TFSI S-Tronic
2015 Pure White 1.2tsi Comfortline
2011 2L BiTdi ROK D/C Highline
2006 Seat Ibiza Cupra TDI
91 Caddy, ADY motor on mp9, wildcat 4-1 branch and 50mm Evolution s/s exhaust
96 1600 Chico (sold)
Tswerie
Enlisted
Posts: 42
Registered for: 6 years 3 months

Re: Engine overheating but radiator is cold

Post by Tswerie »

Thanks, must the radiator be flush or replaced?

Sent from my MAR-LX1M using Tapatalk

Callum229
Cadet
Posts: 251
Registered for: 4 years 1 month
Car Make: VW
Car Model: Jetta MK5 TDI DSG Highline
Location: Durban
Contact:

Re: Engine overheating but radiator is cold

Post by Callum229 »

This could also be a blown head gasket. Reverse flow your radiator(Also check if the radiator is flowing water easily) and remove thermostat and run without thermostat. If problem persists, probably blown head gasket. My lower radiator pipe used to be cold and heater cold as well, remember though, everything has to be checked before going to a headgasket so you have to make sure waterpump is fine, radiator is fine, etc.

What vehicle is it? As @amstel18 says, the wrong coolant definitely can cause serious corrosion issues, so I would suggest immediately removing and flushing your coolant and put in VW G13 with distilled water. Maybe the coolant was not purged properly and there is air in the lines?

If radiator is seriously clogged, you might have to remove it, put in some engine degreaser and leave it overnight and flush it out. Some radiator shops even offer radiator cleaning as well.
2007 VW Jetta MK5 1.9 TDI DSG,

Mods: Simple EGR delete, LED interior set up, LED rear footwell lights, LED Puddle lamps, LED Doorhandle illumination, LED License plate lights, LED Boot lighting.

2007 VW Golf 5 1.9 TDI DSG, no mods.

2007 VW Transporter 2.5 TDI 4motion, no mods.
Tswerie
Enlisted
Posts: 42
Registered for: 6 years 3 months

Re: Engine overheating but radiator is cold

Post by Tswerie »

Thanks, it's a 2010 1.6 polo tdi. 305 000km. After the first pipe burst I have been using cheap coolant

Next step will be to flush radiator then.

Sent from my MAR-LX1M using Tapatalk

Callum229
Cadet
Posts: 251
Registered for: 4 years 1 month
Car Make: VW
Car Model: Jetta MK5 TDI DSG Highline
Location: Durban
Contact:

Re: Engine overheating but radiator is cold

Post by Callum229 »

Yep. flush and check, usually though, if you put a hosepipe on the one side and clamp it and it flows smoothly to the other side, then you should be fine, if not then you have an issue and have to clean it out.
2007 VW Jetta MK5 1.9 TDI DSG,

Mods: Simple EGR delete, LED interior set up, LED rear footwell lights, LED Puddle lamps, LED Doorhandle illumination, LED License plate lights, LED Boot lighting.

2007 VW Golf 5 1.9 TDI DSG, no mods.

2007 VW Transporter 2.5 TDI 4motion, no mods.
Tswerie
Enlisted
Posts: 42
Registered for: 6 years 3 months

Re: Engine overheating but radiator is cold

Post by Tswerie »

Thanks I'll try it

Sent from my MAR-LX1M using Tapatalk

Tswerie
Enlisted
Posts: 42
Registered for: 6 years 3 months

Re: Engine overheating but radiator is cold

Post by Tswerie »

Thanks, did the flush still overheated. Turns out water pump had to be replaced again. The engine is no longer overheating.

Sent from my MAR-LX1M using Tapatalk

Post Reply