After work done, car runs hotter! Thoughts?

Hi all,

I just had my 1995 Z28 worked on a bit and when I got it back, while it runs really nice, it runs a lot hotter than before. I am wondering what I could have had done that would have made the difference as well as if it is a real problem and whether or not I ought to take it back for a look-see.

It's a stock Z28 with nothing done to it by me except for a clean K&N air filter. The mods I had done were as follows:

Eibach drop srpings (1.3") (didn't lower it as much as I would have expected) Eibach anti-roll kit Powerslot rotors/Hawk HPS pads (front and back) KYB gas struts in front and KYB Gas-a-just shocks in back Magnaflow cat back w/muffler BBK 52mm throttle body installed New AC Delco platinum plugs, wires, some hoses replaced and a new thermostat BF Goodrich 27540ZR17 KDWS tires

It rides smooth except over the hardest bumps and handles very well with minimal dive during braking and it remains very flat in the corners. The BFGs replace the Firestone Firehawk SZ50s which they don't make anymore. The suspension results are what I wanted and so far, the tires are performing well.

The problem with the hot engine though confuses me a bit. While running on the freeway, the needle always remained below the first mark. now it's above the first mark, halfway to the second mark. Around town, the needle never got above the second mark unless I was caught in really bad traffic but now it's up to the THIRD mark. Also, the tach is showing idle at 1000 instead of 800. At speed, the tach seems to be at the right numbers (1500 at 65mph).

The only thing I can think of other than maybe a botched radiator servicing is that the new throttle body and exhaust are not working right or maybe the throttle position sensor is out of adjustment. Also, the plugs may not be gapped right. Perhaps the shop just messed something up and it's not something obvious.

I suppose I will have to bring it back and at least ask but I wanted to know if anyone here had an idea of what might be wrong.

Thanks for the help!

snipped-for-privacy@yahoo.com

P.S. This work (including a full clutch job) ran $5600 and I decided to do it to a 10 year old car with 94,000 miles because I can't really afford a new car (busy paying for a house), a used SS would also run me too much and this Z28 is still in great shape and I am very used to it. Might as well keep it at least another 5-10 years if it lasts.

Reply to
Bob Jones
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I thought the ECM had to be reprogrammed to use a new thermostat (I'm assuming, based on my LS1 knowledge, you went from the OEM thermostat to a new lower temp one, perhaps a 160 degree). The computer may have changed the idle to try to compensate; only speculating of course. Other than that, check the air dam to make sure it's not bent or torn.

~w~

Reply to
Weland

I forgot to mention that a couple years ago I changed from the stock

180 to a 160 degree thermostat and there were no issues at that time. I suspect the shop went from my 160 back to a stock 180. I went through the manual and didn't see anything about reprogramming the ECM though. I suppose that might be something to check.

Regardless, wouldn't a thermostat change only the point at which the coolant *started* circulating; using a 180 would result in the temperature needle going higher initially but after the coolant was fully circulating, it ought to drop to its "normal" value an mentioned in my original post and fluctuate between its regular positions.

Oh, and no, the air dam is fine. I'll check the air intake this morning. Maybe something's wrong with the K&N though they said they checked it and it was still pretty clean.

Bob

Reply to
Bob Jones

check the initial timing. All aboard the Yankee express, next stop October.....

Reply to
Hitman0187

if it had a 160 that will make the engine run at 160 all the time.thays what they do.If the shop put a 180 in it that's hotter and the engine will now run at 180 all the time.the exceptions are................startup,it will be cold. heavy load....it will raise coolant temp.remember,horsepower is heat!

Charlie

Reply to
CButtacavo

also keep in mind its a lot hotter outside now then a few months ago. hot air will slow the cooling process All aboard the Yankee express, next stop October.....

Reply to
Hitman0187

I'll be the shop put a 195 degree thermostat. I recently went from a

180 to 195 and the temp guage reads exactly the same as you describe.

The high idle is probably from the idle air intake valve and bypass setup of the new throttle body. It IAT could be stuck or the different throttle body has a different idle air bypass diameter.

Steve...

Reply to
Steve

My only option then is to experiment by replacing it back to a 160 and see what happens! Not that big a deal as it's a quick job but still a hassle.

Thanks,

Bob

Reply to
Bob Jones

Yikes! Why so hot? I thought the idea was to keep the engine cooler to keep the air density a bit higher as well as try to keep detonation from heat down to a minimum. Aren't you worried about harming the block by running too hot?

Hmmmm, could be. I didn't keep the stock throttle body so can't compare and I didn't think to take such measurments beforehand. If it becomes an issue I'll look into if more but for now, it is acceptable.

Thanks for the answers.

Bob

Reply to
Bob Jones

Actually, here in SoCal it's been pretty chilly for May. Hasn't been "hot" in a few weeks now.

Bob

Reply to
Bob Jones

A thermostat does nothing to regulate temperature once it's open. If the fans don't kick in to remove heat from the coolant, then a lower temperature thermostat is netting you very little. A cooler intake charge will reduce the chance of detonation but I don't think that running at designed temperatures will have any adverse effects on the block. If I remember correctly, the fans don't kick in until over 200 degrees anyhow.

-Bruce

Reply to
Bruce Chang

Bob Jones spilled my beer when they jumped on the table and proclaimed in

You're lucky Bob. SBM was telling me that his part of NC has been around high 80's low 90's for a few weeks. Been similar here in Ohio too...which is not normal.

NOI

Reply to
Thund3rstruck_n0i

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