[Dean Asser]

Hey guys, I have a 90 model sj70 sierra. I've swapped the engine out and replaced it with a g13b out of a gti swift. The engine is fully rebuilt with cometic head hasket, arp studs, a new radiator, thermostat, hoses and all, it is currently turbocharged with a gt 2870, small front mount intercooler and a ems stinger computer. I am having issues with the temp creeping up to 3/4 on the gauge whilst under load or a long up hill run. I also have a high speed 11 blade thermo fan fitted in replacement of the original solid hub fan. Any ideas or suggestions how to keep it running cooler? Like going back to the original fan? Larger radiator? ...... if someon else has a similar build to what I have what have you done with your cooling system? ? Any help would be greatly appreciated cheers

[want33s]

Start by fitting a dedicated temp gauge. Don't rely on the factory temp gauge for tuning/diagnostics.
Check that the rad is getting sufficient airflow past the intercooler.
Check the fan isn't running backwards.
etc etc

[Gwagensteve]

First thing I would do is replace the thermo with a vitara viscous fan and a sierra shroud. If this doesn't fix it, then look at a vitara radiator. Thermos on sierra radiators are a bad idea and often won't cool a stock 1.3, let alone a turbo GTi

Steve.

Ps I disagree with want33's a little bit in relation to the gauge. Temp rise is temp rise, the specific numbers aren't all that important. If you want to "calibrate" the stock gauge you could put a thermocouple under the top radiator hose. DMM's with k-type thermocouples are now quite cheap and generally useful. Having two gauges telling you the same information slightly differently is never a good idea.

[droverdave]

Did you use the correct temperature gauge sender unit from your old engine and put it in your new engine? or did you just connect your existing temp guage to whatever sender unit was in the g13b.

[Gwagensteve]

Does it matter? It's not that the gauge is sitting in the wrong spot, it's that it's climbing under load.

Steve.

[droverdave]

hmm true, i just thinking outside the box. Given theres a lot of new cooling system componenets listed there.

You expect it to climb under load a little bit, the wrong temp sender might exadurate it showing it worse than it is.

The other question is how agressive is the tune (given its an aftermarket ecu), as if its a bit lean it might be producing a bit more heat than the cooling system can handle.

[stockman]

This

Gwagensteve wrote:

First thing I would do is replace the thermo with a vitara viscous fan and a sierra shroud. If this doesn't fix it, then look at a vitara radiator. Thermos on sierra radiators are a bad idea and often won't cool a stock 1.3, let alone a turbo GTi

Put up some pics of the engine bay and the front of the car.
What bar do you have on? How big is the intercooler? How did you run the hoses from the back on the motor to the radiator? How long is a piece of string? Has this car been cuzz tech'd?

[shep]

Years ago I owned a swb hardtop with a g16a and stock 1.3 cooling system. 31s 6.5s etc.

When towing my boat the temp used to climb under load with low rpm. I fixed it by pulling the radiator out and taking it to a parts shop to find the biggest thermo that fitted. I put the thermo on a temp switch so it turned on at about 90deg. Never had a issue again even on 45deg days when towing.

[Dean Asser]

I have now done some more changes, haven't yet had a chance to go four wheel driving to test it, I have lowered the intercooler so it isn't blocking the direct air flow to the radiator and also raised the light bar to the top of the bull bar, there is much better air flow to the radiator now, also fitted a make shift snorkel for cooler air induction. It is running a more stable temp up the highway now bit still unsure about how it is off road.