Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Arno on August 29, 2016, 11:22:15 AM

Title: Jeep TJ coolant ??
Post by: Arno on August 29, 2016, 11:22:15 AM

Hi,

I want to flush and replace the coolant on my '05 TJ, 4L

Owners manual suggest using HOAT / G05 coolant, the orange stuff, but I can't find it anywhere in a shop, only online..

Spoke to my local garage, they suggest to flus, drain and replace with G48, the green stuff..this is easily available in shops

I can't find any comparison on the 2 different coolants, so wanna see if any of you have any pointers..?

Title: Re: Jeep TJ coolant ??
Post by: Bradleyu1 on August 29, 2016, 06:53:23 PM

(http://uploads.tapatalk-cdn.com/20160829/a9fa7b3c0d31a6ea6debfe05cb2600f0.jpg)

I used this last time on my TJ 4.0, a mechanic who also runs a 4.0 recommended it.

Title: Re: Jeep TJ coolant ??
Post by: eastryjeep on August 29, 2016, 07:01:41 PM

Just from experience my semi-educated guess is that the difference might have something to do with the proportions of dis-similar metals in the engine.
A BMW engine I rebuilt earlier this year specd G48 - that had an aluminium head and block with wet steel liners and an MX5 lump I did sometime before had an ally head on a steel block which needed G05.
So my guess would be that the higher ratio of wetted iron/steel to aluminium in the engine the more likely you are to need G05 or similar.

Title: Re: Jeep TJ coolant ??
Post by: Arno on August 30, 2016, 07:38:00 PM

Local garage recommend G48, as its also HOAT and very close to G05

Sent from my SM-G935F using Tapatalk

Title: Re: Jeep TJ coolant ??
Post by: eastryjeep on August 30, 2016, 07:50:06 PM

If you've got an ally cylinder head G05 would probably be the best option but G48 wouldn't be a catastrophe.
If head is cast iron or steel G48 would be fine.
Whatever you do you still have the ally thermostat housing which will eat itself anyway!

Title: Re: Jeep TJ coolant ??
Post by: Jonny Jeep on August 30, 2016, 10:35:27 PM

I can't remember what was specced originally for early TJs as I switched to G-05 years ago. It may well have been G-48. The reason for the switch to G-05 is that was used by Mercedes and so Daimler-Chrysler started using g-05 on everything. G-48 will be fine as long as the g-05 is flushed and you change it to schedule.

I'm surprised you can't find any though, I think every car shop round here has it. Comma have a retailer locator on their website that might help you find G-05 locally. Scroll down a bit on the linked page...
http://www.commaoil.com/passenger-vehicles/products/view/354

Title: Re: Jeep TJ coolant ??
Post by: bonza on September 01, 2016, 11:43:52 AM

I got rid of the HOAT type coolant years ago as it left a scum sort of coating on the internals of the radiator eventually blocking up a few tubes and have just used the green type like Castrol Radicool and replace it every two years after a real good flush without any issues like overheating or corrosion