Is 400w hid grow light too hot for plants

No cooltube?

Very vague question dude.
If it's hot on your hand then it's hot on the plants

So i think 26-28 c isn't to hot so try range?

I really don't understand you.
For me, I have air cooled lights. The reason is twofold.
1 it doesn't heat my room up so much.
2 I can get the lights real close to my plants.

So if you aren't having a problem with your grow space being too hot then the question is how close can you get the light to your plants. Use your hand to judge.

Turn on light,wait 15 minutes ,place hand at top of canopy of plant. To hot for your hand=to hot for your plant. Never ever put a hid light with no cooltube closer than 20 inches to a seedling or early veg